Lukasz Korczewski <[log in to unmask]> writes:
> 2. i'd like to use lack-tense vowel opposition. it's clear for me that there
> will be this pairs: (SAMPA again):
> [I][i]    [Y][y]    [U][u]
> [E][e]    [9][2]    [O][o]

Hmm, I never thought [E], [9] and [O] were lax.  But I think the
naming sounds nice in that system.

> (it's like in german)

Almost, yes.

German has the opposition short vs. long.  Then you get the pairs you
showed with the `tense' phonemes being long.  (So in German,
additional to the quality difference, the quantity is different
reflected by the naming convention.)

I said `almost', because German also has [E:] as a long phoneme and
/a/-/a:/ as an additional phoneme pair in the bottom of your schema,
and two Schwas.  The full German system without Schwas is:

 /I/-/i:/   /Y/-/y:/   /U/-/u:/

 /E/-/e:/   /9/-/2:/   /O/-/o:/

The /E:/ is an exception in the otherwise nice system.  (However,
there is a tendency to drop exactly that phoneme nowadays, yielding a
very regular system then.  I think the tendency comes from the north
and moves further south.)

The two Schwas are:
   /@/ (in -e endings:
       `Blume' /blu:m@/)
   /6/ (in -er endings and some diphthongs ending with -r:
       `erster' /"E6st6/ (or /"e:6st6/?, dunno... my dialect...))

(BTW: I even know one chap who learnt High German mainly by reading as
L2 after his L1, the local dialect, and he has a phonemic difference
between /e/ and /E/ so he has the opposition /e/-/e:/ and /E/-/E:/.
That should be an exception, though.)

> but i'm not sure what to do about a's (a, and it's fronted equivalent). in
> german it's smth like this (if i understood it well):
>   [E](with no tack-tense opposition?)    [a][A]

Well, almost, yes.  The [a]-[A:] opposition is found in coastal
dialects in the north only (e.g. in Hamburg) for /a/-/a:/.  They
almost have [{]-[A:] there and possibly even use [{] for /6/:

  Psychiater  /psy:"Ca:t6/ > [psy:\"CA:d{] instead of [psy:\"Ca:t_h6]