kalama pi toki pona

toki pona has 14 (segmental) phonemes, all defined as the IPA standards.  When actually spoken, however, these phonemes are realized in a variety of ways, both predictable and not.  And, in each case, a number of factors enter in that may affect the pronunciation of a particular person on a particular occasion.

To begin at the more predictable end of things.  tp does not have either length of vowels or diphthongs.  But, in practice, stressed vowels are somewhat longer (and usually slightly differently located) than unstressed.  Taking English examples -- which is a bad idea, given the muddled English vowel system, stressed /i/ is probably, in fact,  the diphthong /iy/ while the unstressed is the lower /i/ of "bit".  Similarly with /e/ (/ey/, "bet") and maybe /u/ (/uw/, "hood").  Unstressed /a/ is a schwa (the /a/ in "sofa") and, indeed, unstressed /o/ and /e/ tend that way as well.  Unstressed /o/ moves toward the open o sound but that is often collapsed in English to /a/ and so shift goes on.  Stressed /a/ also often gets (not regularly, apparently) the pronunciation of the /a/ in "hat".  Other substrate languages (and, indeed, other dialects of English) probably have other patterns of difference.  Except in the rare cases where the variation of one vowel goes into the range of another (I live with a speaker who does not reliably distinguish "pin" and "pen" and 'pen" and "pan"), none of these variations are significant for tp.

Much the same is true of the consonants.  The standard for the voiceless stops is unaspirated, but English speakers pretty regularly aspirate word-initial and stress-initial stops.  The standard for /t/ is dental, but English speakers regularly use alveolar.  And so on.  And, again, other languages have other variations.  In particular, an L1 substrate that has nasalized vowels (French, Portuguese, come to mind) will appear in nasalization of word-final /n/ -- and maybe stress-final as well.  Again -- so long as the nasal component remains -- this is not a problem.

But then there are some general phonetic principles in operation which may affect the sound of words.  One is the tendency for consonants between vowels to become voiced, so 'toki' comes out /togi/.  Still not a problem, since there are no voiced-voiceless contrasts in tp.  There is also a (weaker) tendency for stops between vowels to become fricatives, and this could be a problem, if 'mute' came out /muse/ and so fell in with 'musi', say.  So far, I have not heard of a 'p' becoming /f/ or a 'k' becoming /x/, but these would not be problems.  (Well, it might take a minute to get used to the difference from familiar pronunciations, but that is common to all meetings with new people.)

Somewhat harder to cope with -- and potentially more damaging -- are the random changes that apply to just one word at a time.  These tend to be idiosyncratic and based upon experiences unrelated to tp. I offer here just a few examples from my own idiolect and those I have heard:
'lon' pronounced like the name "Lon", tp 'lan', just because of the familiarity
'pona' as /bona/ probably etymological
'pini' as /fini/ also etymological
'musi' as /muzi/ even without general voicing.

Outside of the segmental phonemes, there is one common shift worth mentioning.  It sounds odd but it is not really a problem.  Because of the stress accent patterns of many languages, there is a tendency to take "stress on the first syllable" to mean "stress on the next to last syllable", as it does in most tp words.  As a result, the few three-syllable tp works are pronounced  /-'-/ rather than /'--/.  In at least the case of 'kepeken' this is reinforced etymologically. On the other hand, most three-syllable tp words look Finnish, which reinforces the first syllable rule.  One can imagine cases where this would make a difference, but I have never been able to construct a real one.