You’ll need a synthesiser , (software or hardware) , to play the melody in a sawtooth waveform.
Record that sawtooth melody in Audacity. Use it as a backing-track and make a recording of you saying* the words in time with the melody. Then use a vocoder in Audacity , ( if you want to hear the words clearly use a high-resolution “TalkBox” vocoder , rather than Audacity’s native vocoder ).
[ * singing not required , the sawwave notes will determine the pitch ].