You are correct not to agree with that teacher's statement.

Scat singing of jazz is exactly the same process as an instrument player must go through in order to improvise a solo -- Study of Music Theory, Swing Feel, Chord Progressions, Modes and Scales, plus what is perhaps the most important part of the equation, which is to Transcribe, Transcribe, Transcribe the scat solos of those singers whose work really appeals to you. By "Transcribe" I don't necessarily mean writing it out on paper either, instead, listen to the recording many times over many days until you have the scat solo inside you and can successfully sing it note-for-note, phrase-for-phrase and embellishment-for-embellishment with the original. Then pick another and do it all over again. Etc.

On top of that, don't limit your transcribing to just vocal scat examples, either. Do the same with instrumental solos, be able to sing or whistle or whatever right along with those solos that really grab you. This takes a certain amount of "inundation" with the target recordings on your part. Well worth the time spent.

Ella is an excellent starting (and finishing!) point. Ella could play a mean piano in her own right, BTW, but did not consider herself a pro pianist. Many singers can hold their own at the keyboard, the piano being a wonderful "number line" where all the notes are laid out in front of you. Helps in understanding that theory part, but not all that necessary to wow your audience. Try the transcription of existing scat solos trick. That is the fastest way to get there I know, the rote memorization will satisfy quickly, the fact that you "quote" a famous solo will be appreciated by other musicians and after a while of that you will find that you have your own "pallette" of tricks that you can use in other songs and progressions. LISTEN TO LOTS OF JAZZ AND SWING whenever you can during this period.


--Mac