Sarah Ann Glover and the Tonic Sol-Fa method

Solmization originated during the rise of musical literacy in the Carolingian era, as musical literacy necessitated a way to teach it. In around 795 CE, Charlemagne wrote to the Abbot of Fulda requesting that the bishoprics and monasteries ‘undertake the task of teaching’ because ‘without knowledge it is impossible to do good’ (Treitler Reference Treitler1984: 135). Two hundred years later, Italian music theorist Guido d'Arezzo (c.990–1030) introduced a more precise staff notation along with solmization syllables to make it comprehensible – ut-re-mi-fa-so-la, forming a hexachord. The growth in monastic education, including a literate tradition of hymn-singing, explains Guido's choice of an existing musical text and tune, ‘Ut queant laxis’ (see Figure 1), as the basis for his hexachordal (six-note) solmization system (Boynton Reference Boynton2003: 100).

Figure 1 ‘Ut queant laxis’ on a four-line staff.Footnote ³

In Guido's time, a plurality of notation methods existed with the common goal of transmitting texts with efficiency and fidelity (Treitler Reference Treitler1984: 139, 207). Guido's staff notation and solmization were widely adopted throughout medieval Christian Europe. Staff notation continued to evolve, but the hexachordal system continued to be used for centuries. On the other side of the continent, English choristers at cathedrals and in the Chapel Royal learned to recite the Guidonian gamutFootnote ¹ forwards and backwards well into the nineteenth century (Rainbow Reference Rainbow1967: 14–15). In this same period, a related but modified solmization system was introduced by a Sunday school teacher in Norwich, England.

Sarah Ann Glover (1785–1867) had a conviction that teaching should emphasize practice and that theory should be derived from practice, not the other way around (Bennett Reference Bennett1984: 28). By reducing complexity – ‘inadequate representation of the scale on the staff’, ‘non-accidental sharps and flats’, and the ‘contrivance of clefs’ – Glover could implement practice swiftly (Glover Reference Glover1982: 16–17). Glover's system anglicized Guido's syllables and added a syllable (te) for the seventh degree of the diatonic scale, which had become conventional by the late seventeenth century. Do-re-me-fah-sole-lah-te (Glover's spelling) were used to sing the major scale and the same syllables starting from lah were used for the minor scale. Like Guido, her method included both a notation and a solmization, but with an even more direct connection between the two. In Glover's notation, the pitches are represented by the first letter of the syllable and accompanied by a rhythmic tablature of dots and lines (see Figure 2).

Figure 2 A Yorùbá Christmas song by David Àìná with staff and Sol-Fa notation. (Used by permission of the composer.)Footnote ⁵

Glover's attempts to apply her Sunday School ‘experiments’ in day schools were met with resistance; some believed that teaching music at charity schools might be detrimental to the public good. It was the influence of John Curwen (1816–80) that overrode these concerns. Curwen transformed Glover's Sol-Fa method into a movement aligned with the temperance cause, ensuring that no one could associate Sol-Fa singing with societal ills (Bennett Reference Bennett1984: 29). By the 1850s, the ‘Sol-Faists’ were a community of thousands (see Curwen Reference Curwen1880). The Sol-Fa movement precipitated a musical renaissance in Victorian England but struggled to gain traction with the academic establishment. John Hullah (1812–84), musical inspector for the UK's Council of Education, campaigned against Tonic Sol-Fa in the schools and advocated for a fixed-do system as was taught in much of continental Europe at the time (Leinster-Mackay Reference Leinster-Mackay1981: 165).

Moveable-do systemsFootnote ² have since been adopted widely in English and American music education. However, Glover – and, to a lesser extent, Curwen – has largely been neglected in histories of the period. Despite its tangible impact on amateur singing culture in England, music historian George Grove omitted the Sol-Fa movement in his telling of the Victorian Musical Renaissance (Olwage Reference Olwage2010: 193). In American music education, Zoltán Kodály is given credit for a system he adapted. Sometimes Curwen is cited as his source, but rarely Glover. Bernarr Rainbow drew attention to the efforts of Glover and Curwen in The Land Without Music (Reference Rainbow1967). In several recent books and articles,Footnote ⁴ oversight of Glover has been corrected if not fully recognized. It is doubtful that the Western tonal music system would have had the same impact on music throughout the world without Glover's Tonic Sol-Fa methods. And, perhaps, Christian evangelism would not have been so successful during the colonial era.

In the late nineteenth century, the Tonic Sol-Fa Society joined forces with the missionary movement, similar to the earlier alliance with the temperance movement in the 1840s. In 1857, Curwen began to publish testimonials and reports from stations in Barbados, China, India and throughout the African continent, including one from Old Calabar in present-day Nigeria. A missionary to China, John Fryer, reported that Tonic Sol-Fa ‘formed a bond of union between teachers and pupils’ (McGuire Reference McGuire2009: 130). Although Sol-Fa had been part of missionary activities before, the first missionary trained directly by Curwen was Robert Toy, who was sent to Madagascar in 1862 by the London Missionary Society (LMS) (Southcott Reference Southcott2004: 3). In Madagascar and elsewhere, learning Tonic Sol-Fa, along with European dress and language, became a rite of passage to conversion and an important symbol of control recognized by the colonizers (McGuire Reference McGuire2009: 128). Choral singing became a method of disciplining colonized peoples, demonstrating that they could be civilized through the work of missionaries (Olwage Reference Olwage and Randall2005). An 1890s tour by a black choir from the Cape Colony was designed to impress English audiences, convincing them that non-Europeans could be civilized through missionary education including a healthy dose of Sol-Fa singing. Halfway through the performance, the choir changed from indigenous dress to Victorian clothing, intended and likely received as a ‘serious demonstration’ of progress (Erlmann Reference Erlmann and Lindfors1999: 128).

By the early twentieth century, the Sol-Fa method was present at English- and American-run missions throughout the African continent, often with a diet of simple hymns such as those composed by American evangelist Ira Sankey (1840–1908). The loss of World War I led to the internment of German missionaries and the takeover of their missions by British and American missionaries (Busse Berger Reference Busse Berger2013: 482). As a result, many former German missions (which likely used fixed do) now taught Tonic Sol-Fa with moveable do.

The 1950s and 1960s independence movement largely brought the Protestant missionary era to an end in Africa. Now, many Africans are evangelists of both Christianity and Tonic Sol-Fa. The method also continues to thrive in Asia, in locales as far as Fiji, where it is a mainstay of community singing and a highly effective ‘alternative to staff notation’ (Stevens Reference Stevens2003). In Nigeria in particular, Glover's solmization and notation are well preserved in contemporary musical practice, whereas the method is filtered by Kodály in Europe and the United States, and Glover's notation absent. Sarah Ann Glover's invigoration of moveable do has had a profound impact on Western music education, but even more directly on music practice in former colonies. Although Glover surely did not know it, the use of moveable do made the Tonic Sol-Fa method more sympathetic to the intertwined musical and linguistic tone systems of Niger-Congo cultures. Fixed do, in which each solmization syllable is tied to an absolute pitch, is dependent on the availability of instruments with standardized tuning and requires a significant amount of formal training before it can be used. Moveable do, as a relative pitch system, is not and does not. To illustrate the lack of, and even resistance to, standard tuning in indigenous African music, Kavyu offers the anecdote of a 1971 cultural workshop at the Institute of African Studies in Nairobi, Kenya. A group of lyre players from across Kenya were gathered and asked to tune their lyres to the same pitch level. While it may have satisfied the organizers for lyrists of many different ethnicities to play in concert, it was disorienting to the musicians (Kavyu Reference Kavyu1977: 31). Èkwúèmé suggests that diatonicism (scale systems similar to the Western major and minor scale) existed in Africa before the arrival of missionaries (Èkwúèmé Reference Èkwúèmé1974: 52). However, standardized tuning certainly did not. Moveable do is much more adaptable to different instruments and voice ranges, and in its reliance on relative pitch recognition perceptually similar to the contrastive lexical tone of Niger-Congo languages.

Samuel Àjàyí Crowther and African tone systems

For centuries, the ports at Badagry and Ouidah in the Bight of Benin were busy with human trafficking to Brazil, Cuba, Haiti and elsewhere. Many of the people traded at these ports belong to what is now known as the Yorùbá ethnic group. As a result, aspects of Yorùbá culture, including the language, religion, food and music, are now found throughout the Americas as well as in their ancestral home in present-day Nigeria and Benin. The act abolishing British involvement in the slave trade was passed by the British parliament in 1807. Soon afterwards, the Royal Navy began intercepting outbound slave ships along the West African coast. On one of these ships was a young man, Àjàyí, who would be reborn as Samuel Crowther (1809–91) in the missionary community in Freetown, Sierra Leone.

Crowther received his doctorate in divinity from the University of Oxford in 1864. His identity as a ‘Black Bishop’ piqued the interest of evangelical communities in London and New York, where multiple biographies were published (see Figure 3). His legacy in Nigeria is closely tied to the publishing of the first Yorùbá primer and vocabulary in 1843 and a complete orthography, grammar and dictionary in 1852. Crowther went on to publish primers and vocabularies for Igbo (1857) and Nupe (1860 and 1864).

Figure 3 Bishop Crowther (1867).Footnote ⁶

Like Crowther, many of those freed from slave ships and educated in Freetown eventually returned to their homelands. In the Niger territory, they were known as Sàrós (after Sierra Leone) and occupied esteemed, but ultimately restricted, positions within the colonial system. As bureaucrats, clergy and educationists, the repatriates utilized dual identities of being Africans and Western-educated Christians to mediate between the colonists and the colonized. Crowther's development of a Yorùbá orthography aided the colonization and evangelism of Yorùbá-speaking areas, forever changing the society. At the same time, the early adoption and sustained use of a Romanized orthography have contributed to an ethnolinguistic culture that continues to be robust in the twenty-first century while the majority of African languages are in decline.

Crowther's first task was to create a pan-Yorùbá identity by collapsing the dialects:

Because Crowther recognized Ọ̀yọ́ as the capital, Ọ̀yọ́ dialect became the model for Standard Yorùbá (SY). The Church Missionary Society (CMS) became the arbiter of Yorùbá literacy. In 1875, the CMS convened a conference to standardize the Romanized orthography, a disappointment to Muslim Yorùbá scholars then and now (Ogunbiyi Reference Ogunbiyi2003: 77). Despite this, Yorùbá people are united by their language and are not prone to the intra-ethnic religious conflict consuming northern Nigeria in the twenty-first century.

The success of the civilizing mission among the Yorùbá was lauded by general reports from the missionary field:

While Cust was a bit off on the spelling, his prediction about Yorùbá’s virility in the future was correct. English is the national language of Nigeria, but Yorùbá people continue to take pride in their language and cultivate a pan-Yorùbá identity around it, ignoring smaller differences in dialect and custom, and sometimes major differences in religious belief. Elsewhere in the book, Cust also noted a peculiar aspect of Crowther's approach to orthography: Crowther insisted on the importance of tones in both the language and the orthography (Cust Reference Cust1883: 229). Cust's survey of the missionary field makes it clear that Crowther's emphasis on tone was novel at the time. Analogies between tone-language speech and musical melody are now known to Western scholars, but at the time Crowther's description must have struck readers as extraordinary.

When Crowther developed the orthography in the 1840s, there was no precedent for accommodating the strong presence of lexical tone found in many Niger-Congo languages. Over 40 per cent of the disyllables depend on tone to be differentiated from other entries in the concise and widely available Yorùbá dictionary published by Ìbàdàn University Press Yorùbá. In a more thorough dictionary, such as Abraham's (Reference Abraham1962), I would expect this percentage to be higher. There is a comparison to lexical tone in Chinese in the preface to the 1852 edition. However, the Romanized script for Chinese with diacritics, Pīnyīn, was not developed until the twentieth century. It is not made explicit, but it is likely that the polytonic orthography for ancient and medieval Greek pitch accents – (´) for high, (`) for low – was the closest model available to Crowther.

Crowther's prescription for marking tones has been sustained and developed in Ayo Bamgboṣe's orthography (first published in 1966), which is the basis for the Academy of African Languages’ (ACALAN) Yorùbá writing manual. However, tone-marking remains alternately bewildering and irritating to some fluent speakers and a recent dictionary advocates ‘eliminating the tonal signs’ (Fakinlede Reference Fakinlede2003: 9). The concept of lexical tone was almost inconceivable to missionaries who spoke only European languages without contrastive lexical tone. The missionaries approached orthography for the hundreds of languages in Africa from a very different perspective. Crowther had a distinct advantage of being a first-language (L1) speaker of Yorùbá who had immersive training in English. Of the European missionary linguists, Johann Gottlieb Christaller (1827–95) of Basel was unique in his careful consideration of West African tone systems (Bearth Reference Bearth and Jenkins1998: 85). Written some years later and describing Akan in the Gold Coast (Ghana), Christaller's description of Niger-Congo tonology is largely consistent with Crowther's and likely influenced by it.

Some sceptics still doubt the necessity of marking tone for a language such as Yorùbá or Akan. However, if one accepts that marking tone is necessary, the issue then becomes efficiency: should tone always be marked or just when it provides lexical contrast? There are many words of the same class – noun and noun, verb and verb – in which vowels or consonants are allophonic (non-contrastive) while tone is phonemic (contrastive). Are these the only words in which tones should be marked? What about the syllables themselves? Should all syllables within a word carry diacritics? While these are no longer controversies among modern linguists, Crowther and Christaller grappled with these issues. Crowther's method was to mark the first high or low tone in a sequence of consecutive high or low tones, so that the second syllable would be marked only in a four-syllable word of mid-high-high-high tones.

Table 1 Examples of words with multiple marked tones (from Crowther Reference Crowther1852: 4–5).

In the examples Crowther offers (see Table 1), leaving repeated high or low tones unmarked is more efficient because fewer diacritics are necessary. However, his tone-marking does not accommodate a return to the unmarked (mid- or neutral) level after a marked (high or low) tone that cannot be indicated. This is problematic for the tonally contrastive minimal pair in Table 2.

Table 2 Tonal variants of the [mimɔ] homophone.

Two versions of the homophone [mimɔ] are written in exactly the same way using Crowther's orthography, even though they are pronounced differently and have distinct meanings. In Bamgboṣe's orthography (first published in 1966), each occurrence of high or low is marked, solving the problem.

Christaller's system largely followed Crowther's in terms of leaving consecutive equal tones unmarked but introduced some complex rules for step tones and short vowels (Christaller Reference Christaller1875: 15). While Reverend Christaller had a much greater sensitivity to tone than the vast majority of missionary linguists, he adopted a laissez-faire attitude about when tone marks should be applied:

However, in the preface, Christaller admits:

Both Crowther's and Christaller's early treatments of tone had inadequacies that have been corrected by recent orthographies, but their methods continued to be used largely intact for nearly a century. In the late twentieth century, formal linguistics grew immensely, and, along with it, the study of tone. Much like the misattribution of Sarah Ann Glover's Tonic Sol-Fa method, linguists have often cited Christaller as the progenitor of tone-marking in African languages, not Crowther.

What is the difference between tone and tune?

Ignorance among missionaries about the importance of tone is manifested in metric translations of hymn texts into African languages. The singing of the translations to standard tunes has produced hymns of utter nonsense across West Africa (Parrinder Reference Parrinder1956: 37) as well as in Asia and the Americas. For a well-documented language such as Yorùbá, with a published vocabulary available since 1843, those who undertook these translations had the resources available to be more sensitive to tone. One may speculate that they chose to ignore tone. The response among Yorùbá Anglicans was to add ‘native airs’ to the hymnbook, explained by Reverend J. J. Ransome-Kuti (grandfather of Fẹlá Kuti) in his preface:

The native airs, though cognizant of tone, were decidedly Westernized. Comparative musicologist Erich von Hornbostel suggested that, in lieu of European hymns or hymns composed in a European fashion, African converts be encouraged to ‘sing and play after their own natural manner’ (Reference von Hornbostel1928: 62). This musical practice was pioneered in the Africanized Aládùúrá churches early on, but it was not until the postcolonial era that a more ‘natural manner’ spread to Catholic and Protestant churches, where European hymns in both foreign and indigenous languages are sung alongside praise choruses to this day. Agu indicates that the true fault of the hymns is not the linguistic defects – people have come to recognize the intended meaning: the problem is that one cannot dance to them (Reference Agu1992: 14). However, I have seen this shortcoming of hymns overcome on many occasions.

Linguists and ethnomusicologists have explored correspondence between speech tones and musical tunes for nearly a century. The first major article on the subject, Herzog's ‘Speech-melody and primitive music’, states that a strict representation of speech melody by musical melody is not implied (Reference Herzog1934: 466). However, if a melody ascends in pitch where a spoken contour would descend, it is a problem for lyric intelligibility. The Yorùbá text ‘Wá s’ádúrà ŏrọ̀’ means ‘Come to morning prayer’ with the proper tone, but when the text is sung to the melody in Figure 4 the last word sounds like ‘ŏrọ’ (crippled).

Figure 4 From the hymn tune ‘Venice’ (1853) by William Amps.Footnote ⁷

The Yorùbá text ‘Nkọ̀ jẹ́ gbẹ́kẹ̀lẹ́ ohun kan’ means ‘I will not ever hope in one thing’ with the proper tone. However, when it is sung to the melody in Figure 5 it sounds more like ‘I will not eat hope in one voice’.

Figure 5 From the hymn tune ‘Solid Rock’ (1834) by Edward Mote.Footnote ⁸

Because of the potential for tone–tune mismatch, it is ideal to compose a melody to a text. Beyond one-to-one correspondence, there is a more general incongruence between the contours of Niger-Congo languages and the aesthetics of European music. ‘Nkọ̀ jẹ́ gbẹ́kẹ̀lẹ́ ohun kan’ has a tone sequence of MLHHLHMMM, including no fewer than four changes of direction. The corresponding melody of ‘Solid Rock’ contains only one change of direction, forming a melodic arch ascending for three beats then descending for three beats. A melody composed based on the text would be more angular, with more frequent changes of direction.

Indeed, the general angularity of Niger-Congo tone-language speech is reflected in the melodic character of the music. Kolinski describes a song from Dahomey (see Figure 6), a neighbouring kingdom to Ọ̀yọ́, as ‘bold and ragged’ (Reference Kolinski1965: 116). Kolinski's Western-acculturated ears underlie his pejorative assessment, since they are accustomed to small intervals between pitches (steps and skips), which are fairly continuous in direction, and less frequent large intervals (leaps) and changes in direction. Different language typologies correspond to distinctive musical aesthetics.

Figure 6 Transcription of a Dahomean song.Footnote ⁹

If one wonders whether the analogy between music and language in Yorùbá culture originated with Crowther's comment in his preface to the 1852 orthography – ‘the Yorùbá language is very musical’ – the answer is most likely no. Speech surrogate instruments that serve both as signal and entertainment are found in many tone-language cultures in Africa, from the iconic Yorùbá dùndún (double-membrane hourglass-shaped talking drums) to sets of pitched ideophones among the Ìgbò (including the ògénè bells and ùdù pot drums). Long into the past, Yorùbá praise poets and dùndún players (who often work in tandem) must have understood a connection between the pitch effects of decreasing and increasing the tension of the leather bands of the drum and manipulating the human voice because they would imitate each other in antiphonal performance. Nigeria's first professor of music, Ígwē Laz Èkwúèmé, was the fifth thesis advisee of celebrated music theorist Allen Forte (Carson Berry Reference Carson Berry2009: 214). Èkwúèmé rejects missionary-turned-musicologist A. M. Jones’ contention that Africans are unconscious of any organized theory behind their music. He cites examples of ethnolinguistic groups that have concepts similar to a tonal centre around which notes revolve (Èkwúèmé Reference Èkwúèmé1974: 35–6). Later in the same article, he comments on scales:

Although anachronistic, Èkwúèmé’s attempts to reconcile the diatonic scale and African pitch systems must have some grain of truth: how else could Tonic Sol-Fa so quickly take hold in so many cultures in sub-Saharan Africa? The responsiveness of each culture to Tonic Sol-Fa likely varied, and may have done so in accordance with the nature of the instruments already present within the culture. Wolfe and Schubert (Reference Wolfe and Schubert2010; Schubert and Wolfe Reference Schubert and Wolfe2013) argue that stable pitch in singing is unnatural and is influenced by pitched musical instruments. If this is the case, at least in some African cultures, stable pitch in voice was probably already present in cultures with stable pitch instruments, such as the lamellophone (thumb piano). In others, Tonic Sol-Fa may well have introduced singing on a relatively stable pitch. Èkwúèmé points out that spoken pitch is less definite than sung pitch and that slides and glissandi are present in singing, but states that these ‘should be ignored in an attempt to determine a scale’ (Èkwúèmé Reference Èkwúèmé1974: 52). In Èkwúèmé’s Ìgbò language, speech tones and the pitches of speech-surrogate instruments tend to be discrete (delineated and stable pitch). Thus, the assumption of Tonic Sol-Fa – people sing on a level pitch – is compatible. However, in Yorùbá, sloped pitches (falling or rising contour) are found within a vowel segment and the instruments also produce glissandi. Yet, Tonic Sol-Fa, including the notation, was heartily adopted and adapted into Yorùbá Christian culture and is now a common method for choral singing. While the portamenti and glissandi of Yorùbá tones and talking drums are still extant, the solmization syllables do-re-mi have come to inform conceptions about pitch in unexpected ways.

In 2013, the BBC World Service broadcast a programme on the ‘thriving music and art scene’ in Lagos, Nigeria. During a visit to the Musical Society of Nigeria on Lagos Island, Will Ross interviewed several students in the diploma programme:

When the music student Àlàbá (tones: low-low-high) uses the xylophone to teach the lexical tone of his name, he is using the do-re-mi heuristic. Another name with the same tone contour as Àlàbá is Crowther's Yorùbá name: Àjàyí (also low-low-high). What is glossed over by the do-re-mi heuristic is the articulatory detail that the first low tone typically has a falling contour and the high tone following a low tone has a rising contour in fluent speech. However, the concept of the relative pitch heights (if not the pitch trajectories) is preserved. Unsurprisingly, the first reference to both Sol-Fa and Yorùbá tone in the same manuscript is made by a musician, Thomas Ekundayo Phillips, a former organist of Christ Church Cathedral in Lagos, not far from the Musical Society.

Phillips is also the first, to my knowledge, to point out in published literature that the positions of the tones are not fixed. Acoustic analysis suggests that a wider range than do-re-mi (four semitones) is more characteristic of recorded speech. Do-mi-so (seven semitones) is more similar to the spacing than do-re-mi (Carter-Ényì Reference Carter-Ényì2016: 155). To use any solmization syllable suggests that speech tones are stable pitches. Drawing on a staff gives the option of indicating contours by connecting pitch events across the lines and spaces, through portamento and glissando. This is useful because there are circumstances in which tones are stable and others in which tones are sloped. In ‘The assimilated low tone’, Bamgboṣe describes the circumstances under which low tone has level pitch (after a low tone) and is low-falling (after a mid or high) (Reference Bamgboṣe1966). In his grammar, Bamgboṣe explains that high becomes low-rising after low and mid is low-mid after low (Reference Bamgboṣe2010: 9). Although capable of indicating these pitch trajectories, Phillips’ suggestion of using the staff is more elaborate than the simple diacritics so many already find cumbersome, and is more appropriate for transcription than a streamlined orthography. The musical staff has been used as Phillips suggested by music researchers, for example in Adégbìtè’s study of oríkì (Reference Adégbìté1978). The comparison of tones to musical pitches is not restricted to musicians; linguists have also contributed to the conflation. Writing on another Nigerian language, Jukun, Welmers states:

While the tones may be understood if sung on do-mi-so, the phonetic implementation in speech is often more complex than Welmers describes. As Welmers suggests, playing speech tones on a piano does not ‘appreciably distort’ the tones, but it does not capture the full story either. A variable-tension talking drum (such as the dùndún) is much more capable of representing the speech contours. In addition to the sloped contours (rising and falling tones) that Bamgboṣe describes, production and intonational effects during fluent speech such as downstep and high-rising put tone levels in constant flux (Laniran and Clements Reference Laniran and Clements2003: 203). Despite the complexity of African tone systems and the manifold ways in which musical pitches are not like speech tones, the do-re-mi folk heuristic has gained traction with the Christianized public and within the academy in Nigeria. A popular text found in street markets and used in secondary schools includes Hausa, Ìgbò and Yorùbá vocabulary (the three major indigenous languages of Nigeria) and was written to ‘generate unity’. Yorùbá is the only language in the text for which tones are marked: ‘accents are used over Yorùbá words to denote their sounds which are doo, ree, mii … ree has no visible tone mark except on nasalized syllables’ (Odetunde Reference Odetunde2009: 1). According to the brief biography included in the book, Odetunde is a bit of a renaissance man with an interest in languages but little formal training. A foreign text by a bona fide linguist, Professor Antonia (Yetunde Folarin) Schleicher of Indiana University, also uses the same folk heuristic:

Although Schleicher is targeting a non-Yorùbá audience, schoolteachers and even linguists in Nigeria use the do-re-mi heuristic to describe the tone levels to fluent speakers working on Yorùbá literacy. I have also observed people with Yorùbá literacy use do-re-mi as a mnemonic aid in transcribing speech to text. Do they have experience singing in a choir using the Tonic Sol-Fa method? Most likely; many Nigerians do.

The current orthography, reflected in Bamgboṣe's grammar (first published in 1966), makes the analogy more appropriate, because the underlying tones are all conceived as discrete (low, mid or high). To manage this, he divides long syllables with contour tones into smaller units: ‘The so-called glides … recognised as additional tones by many scholars … are treated in this system as separate tones occurring on a sequence of two syllables’ (Bamgboṣe Reference Bamgboṣe2010: 6). A new Yorùbá grammar by Rutgers University professor Akinlabi is forthcoming. Some years back, in a chapter for laypeople on Yorùbá orthography, he stated:

Akinlabi's research has covered complex and novel topics such as under-specification and clitic assimilation of tone, all of which point to the relationality of tone. Yet, for a description for laypeople, Akinlabi's illustration of phonemic tone does not deviate from Crowther's description 150 years earlier. Both used monosyllables to introduce the concept. Despite a century of research, the basic concept of the tonemes as ‘atomic units’ has not changed. Shortly before his death, tonologist Nick Clements questioned whether tone features were motivated at all, reasserting that they ‘do not serve the same functions as segmental features’ (Clements et al. Reference Clements, Michaud, Patin and Hume2011: 3), similar to Lehiste (Reference Lehiste1970). Akinlabi's example of a monosyllable homophone with three distinct tones, like Crowther's example 150 years earlier, is misleading because it is not clear how an isolated syllable can have contrastive tone, except by using extreme parts of one's voice range. Elsewhere, I provide empirical and experimental evidence that high and low tones spoken in the upper or lower part of a speaker's range are intelligible and that tone levels are perceived syntagmatically, as relative pitches (Carter-Ényì Reference Carter-Ényì2016: 156). This is implied in Crowther's and Christaller's early descriptions, using words such as ‘relative’, or ‘elevation’ and ‘depression’ of intonation. From my experiments (ibid.: 147–55), it is clear how two or more syllables may be perceived as having high or low tone levels in relation to each other, but it is unclear how tone may be an isolated (or paradigmatic) unit, perceived through absolute pitch. However, the temptation to use a monosyllable example persists. Segmental features, such as those that combine to create /a/ (+open, +back)Footnote ¹¹ are easily discretized because they are absolute (paradigmatic) features. However, tone features may be perceived in terms of relative pitch (syntagmatic relationships).Footnote ¹² Although the conflation of tone and tune is not without its faults, the folk heuristic of do-re-mi, implying moveable pitch relationships, has advantages over the atomic units low, mid and high.Footnote ¹³