It is a cool idea! I've had a bit of experience with building synths in decker, and tbh like I don't want to discourage you but for a first time programming task it's got a fair bit of complexity to it, since you'll have to build both the synthesis engine and the interface that drives it. Like it IS absolutely possible, albeit limited by Decker's audio output capabilities. But you'll need to work out first the principles of how to actually generate the waveforms for the notes and implement that in Lil, and then how to string them all together sequencer-style. Absolutely doable if you've got some programming chops but if you've really never programmed before I'd encourage you to start with something a bit easier.

These sorts of sequencers work based on pitching samples of syllables up and down, right? So to start you'd need to get a sound back of syllables and work out how to pitch them up and down. I'm not sure if just adjusting the speed would work or if you'd need to do something time-stretchy so they're all the same length. Either way there'd probably be some somewhat gnarly maths around resampling the audio to different pitches.

Once you can get the notes generating, to be honest the actual tracker side of things may be a bit simpler - the way I did it was just using a table and iterating through that when it plays back.

If you do manage to get something working I'd love to see it! But for a first time programming project it feels like it'd be a bit of a trial by fire. I really don't want to discourage you but I also don't want to see you get discouraged yourself by aiming too high for your first attempt.