During the past few years linguists have begun to express doubts about the validity of segmental analysis for the study of child language and have come to feel that it is probable that a child perceives spoken language differently from an adult, e.g. Bellugi & Brown (1964: 113), Ingram (1966: 218), Ladefoged (1967: 148–9), Lenneberg (1967: 279–281), Weir (1962: 30). They are also beginning to realize the importance of treating a child's language as having its own independent system (Carroll, 1961: 332; Fry, 1966: 194). To date, however, investigators of child speech have made their analyses on a segmental and distributional basis and have expressed the child's phonological system in terms of the adult's phonemic system; one may cite for example Cohen (1969), Grégoire (1933, 1947), Jakobson (1941), Jakobson & Halle (1961), Leopold (1939, 1947, 1961), Lewis (1968), Ohnesorg (1959), Velten (1943) and Weir (1962). Such studies, valuable though they be, cannot be said to have succeeded in explaining the relationship between the forms and structures of child and adult and have left many questions unanswered such as:
(1) What governs the choice of sound that the child will use as a ‘substitute’ for an adult sound?
(2) Why does the child ‘drop’ certain sounds of the adult form or ‘substitute’ for them when he is already capable of making such sounds and is in factusing them in some other contexts?
(3) Why does the child use homonyms for adult forms which appear to be quite unlike each other and which have been proved to be semantically clearly differentiated for the child?
(4) What governs the form that reduplicated words take?