yes, alto is the foundational sax. if you have to learn on anything, it sould be alto, if not it should atleast be tenor. Tenor requires more air. But soprano requires more everything. Stronger embouchure, aire, tone control, INTONATION (strong embouchure again), dexterity and more accuracy on keys that are like half the size of regular ones.
Im not saying its impossible to learn on soprano, just not reccommended
CSE2