There seems no doubt, by the same evidence, that a long y of older Cornish often became i, as in the English word mine. Vulgarly, as with the English long i, it sometimes even became oy. Boson writes choy for chy, house, but Lhuyd writes it tshyi or tshei, which last is its usual modern sound in place-names. Nŷ, we, whŷ, you, jŷ, they, and hŷ, she, are written nei, huei, dzhei, hei, by Lhuyd, and Jenkins of Alverton, using the earlier form of the third person plural, written y in the Dramas, spells it eye. Yet there are cases where the older pronunciation is retained, and probably this was always the case when the words were enclitic. Prof. Loth has pointed out a similar change in the Quiberon sub-dialect of Vannetais Breton, and that in some of the same words.
In the unscientific spelling of the seventeenth and eighteenth centuries, that is to say, in the system of every one except Lhuyd, and occasionally of Gwavas and Tonkin when they followed Lhuyd, the English values of the period were often given to the letters; but the following were vowel symbols in general use:—
| For | â of the | present system, | a, aa | Lhuyd | â. |
| For„ | a | present„ system,„ | a, u, e, o | Lhuyd„ | a. |
| For„ | ê | present„ system,„ | ea | Lhuyd„ | e. |
| For„ | e | present„ system,„ | e, i | Lhuyd„ | e. |
| For„ | î | present„ system,„ | ee | Lhuyd„ | î,ŷ |
| For„ | i | present„ system,„ | i | Lhuyd„ | i. |
| For„ | ô, | present„ system,„ | oa, o, aw,au, ao | Lhuyd, writes , an inverted a or ô. | |
| For„ | o | present„ system,„ | o | Lhuyd | o. |
| For„ | ǒ, ŭ, ǎ | of the„ present„ system,„ | o | Lhuyd„ | ẏ. |
| For„ | û,ou | present„ system,„ | o, u, a, e | Lhuyd„ | ụ, û. |
| For„ | ow | present„ system,„ | ô, ow, ou, au | Lhuyd„ | oụ, o, ô. |
| For„ | u | present„ system,„ | u, oo | Lhuyd„ | u. |
| For„ | ew, yu, eu | present„ system,„ | ew, yu, yw | Lhuyd„ | iụ,yụ,eụ |
| For„ | ŷ, ei, ay | present„ system,„ | y, ei, ay | Lhuyd„ | ei, y, yi |
| For„ | y, | present„ system,„ | y, i, e | Lhuyd„ | y, i |
A final e mute was often used to lengthen a vowel, as in English. Many names of places and persons retain
