Here's a scenario:
You're in a small village somewhere in the world. You have a laptop and you also have a vocabulary list for a language spoken in that village. You politely ask a native speaker if he or she can spare some time. You sit the person down in front of your laptop and explain to the person that you would like her to watch a slide show of vocabulary. You explain that as she is watching the show, you would like her to read each vocabulary term aloud as it appears. The program will be recording her voice.
Kanji Crammer will now also prompt with pictures.
As you go from village to village, you collect these recordings. The files will be tagged with the speakers name and the vocabulary terms.
Sounds interesting? Are you booking your flights now? No need! Unless you live where there are no other people, there is plenty of data to be collected where you live.
What do you do with this data when you have collected all of it? While this is not the place for an introduction to phonology, as you move from place to place, the kinds of things that phonologists have an interest are:
vowel formants: what is the constellation of a person's vowels in a vowel chart?
tone: what is the range and contours of tones that a speaker has?
voicing: what consonants are voiced? what consonants are not voiced?
manner and location: where and how are these consonants pronounced?