Joseph Fatula, On 06/06/2007 10:51:
> I'm having a problem analyzing the phonemes of a language.  The sound 
> [e] only appears before voiceless consonants, while [i] can appear in 
> any other environment.  This leads me to think that they're allophones 
> of each other, except for the following problem.  Voiceless fricatives 
> become voiced between vowels, yet the [e] in such cases remains unchanged:
>   - [nef] > [neva]
>   - [niv] > [niva]
> Among words with the "-a" suffix, this [e] vs. [i] distinction is the 
> only thing showing the difference between words like [neva] and [niva].  
> Are these minimal pairs?  Are [e] and [i] separate phonemes?

IMO, we're definitely dealing with one phoneme, if [neva] is never monomorphemic. 

/nif/ [nef]
/niv/ [niv]
/nif + a/ [neva]
/niv + a/ [niva]

(The "IMO" is important, bcs I insist on morpheme boundaries' visibility to phonology.)

With nods to Roger's excellent msgs in this thread.