pronounce

[Unregistered]

how to pronounce Mpemba

[Soup]

In Swahili the syllable "m" doesn't merge with the following consonant and should be pronounced somewhat like "humm!".

[Raymott]

In Swahili the syllable "m" doesn't merge with the following consonant and should be pronounced somewhat like "humm!".

But if the /M/ is pronounced "humm" (is the ! a click?), then Mpemba would be pronounced Hummpemba, in which case the "m" does merge with the /p/.
I don't know the answer to this, but I always hear the former South African President's name pronounced /əm’beki/ not /mə’beki/, which seem to be the most likely two options.

[Soup]

But if the /M/ is pronounced "humm" (is the ! a click?)

No.

Mpemba, [m] is syllabic; you can sing it.

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Swahili has prenasalized stops (e.g., [mb]) as well as prefixal /m-/ (e.g., m- 'person' + pemba 'ignorant').

[Raymott]

how to pronounce Mpemba

Well, there you are Guest. You hum or sing the /M/, then, without merging the /M/ with the /P/ you say pemba. There may be further vocal calisthenics to do with second /M/ before the final /ba/; but let's practice walking before we attempt to run.