The spelling of a "more or less unwritten" language may open up for a number of interesting challenges. Nyakyusa has but a few, however they should be resolved in a proper way and future printed materials in Nyakyusa should as far as possible follow whatever can be agreed upon as a standard.
One main problem with languages being put into written form by untrained people is that many of them seem to believe that every language should be spelled like English. The scary part is that even the newest bible translation (into Konde) follows this 26 letter system. Luckily, some of the people dealing with Nyakyusa around 1900, had more of a linguistic common sense.
As can be seen explained in the Nyakyusa dictionary, Nyakyusa has 30 phonemes, 7 of which are long vowels (written double).
Issue #1 Vowels
Having 7 vowels already creates a problem from the English or Swahili list of letters. Early writers added the two symbols i-underdot (unicode ị) and u-underdot (unicode ụ) for the two additional symbols necessary.
In 1996 when the Nyakyusa dictionary was sent to the printer, we were in PC-neanderthal times and so the letters i-accent-aigü (í) and u-accent-aigü (ú) were chosen. This was to be honest more from a keyboard practicality point of view anno 1996 than anything else. From an English/Swahili perspective it may not be a bad choice, but from a general Bantu perspective where these symbols frequently symbolize tonal distinction they may not be so smart. Nyakyusa not having tones, this is of course not of local relevance.
Whichever way one looks at it, the important thing is to distinguish the two extra vowel sounds in writing.
Issue #2 the letters NG' NG and ND
Again following convention, the letter NG' (representing the final consonant sound in the English word "sing") to be distinguished from the letter combination NG (representing the consonant cluster sound in the English word "finger") is a spelling convention from Swahili.
The letter D does not really exist, exept after N, which possibly indicates a voiced T rather than a D. The pronunciation however, is clear.
Issue #3 the -NYA- and -NÍA- combinations
Does anyone have a better solution?