Translate and Transcribe Swahili audio to written English

Translate and transcribe ~350 short audio files from Swahili to English. We have Swahili audio and we need written English (we don't need any intermediate steps; ie. written Swahili). These audio files are short; the average length is 15 seconds and people are generally speaking for a fraction of that, often only a single word.

The audio recordings are people answering this question:
Please tell us in your own words what Internet.org is used for?

One example file is attached below to give you an idea of the length and content in the responses.

We have 346 audio files, and will pay $0.30/file transcribed and $0.15/empty file identified (one without content in the form of an answer). Ideally, we would like the translation and transcription completed by Wednesday, July 15th and would like to confirm a contract ASAP.

IMPORTANT: When you submit a proposal, please include your sample transcription of the attached audio file.

(The number in the budget field is ~(346 files * $0.25/file) as we expect some files to be empty, the final payment will be determined at the end of the job when we count the number of empty vs. transcribed files.)