It seemed like a good idea at the time, but it clearly confuses a lot of people.
Like many other phoneticians of English, for the past twenty-odd years I have been using the symbol i to represent the weak ‘happY’ vowel used in positions where the FLEECE-KIT distinction, iː vs. ɪ, is neutralized, and where an older generation of RP speakers used a lax [ɪ] but a younger generation tend to prefer a tense [i].
Veronica Varela asked:
Is there any rule for the use of i and u (neither long nor short?
euphoria ju ˈfɔːr i‿ə
bizarre bɪ ˈzɑː bə- ǁ -ˈzɑːr
behind bi ˈhaɪnd bə-
In the case of bizarre we use ɪ and for behind i. What is the difference?
My reply went along the following lines.
The symbol i does not mean “neither long nor short”. It means that RP traditionally has lax ɪ in these positions, but that many speakers nowadays use a tense vowel like iː. Therefore the EFL learner may use one or the other indifferently in these cases, because it does not make any difference whether the vowel is tense or lax. See further the discussion in LPD under "Neutralization" (p. 539 in the third edition).
In LPD I use the symbol i in those cases where some people have a tense vowel in place of the traditional RP lax vowel: namely, in weak positions that are
- (a) word-final, as happy, coffee, valley,
- (b) prevocalic, as various, euphoria,
- (c) in the unstressed prefixes be-, de-, pre-, re- and certain word-like combining forms such as poly-.
As far as I know, no one uses a tense vowel in bizarre, whereas in behind and other be- words some people do.
If all this is too complicated to teach, tell people that they should interpret i (without length marks) as meaning the same as ɪ (the KIT vowel). That might make them sound a bit old-fashioned (like me), but nothing worse.
I might have gone on, but didn’t, to discuss the theoretical idea that English has a weak vowel system as well as a strong vowel system; the weak vowels are found exclusively in unstressed positions, and are those vowels which can result from vowel weakening in the lexicon. Pairs such as vary, variety demonstrate that i acts as the weak counterpart of aɪ. The strong and weak forms of me, she etc demonstrate that it also acts as the weak counterpart of iː.
All the above applies, mutatis mutandis, to u (“sitUation”).
Perhaps this is another case of the conflict between on the one hand trying to accurately document the phonetics and phonology of English and on the other hand presenting a convenient simplified distillation for pedagogical EFL purposes.