to'a BY1 cmavo

lower-case letteral shift.

On affix form:

tonga
x1 is a tone/note of frequency/pitch x2 from source x3.

In notes:

to'alfu
x1 (la'e zo BY/word-bu) is a lower-case letter/digit/symbol in alphabet/character-set x2 representing x3.
ga'e zei lerfu
x1 (la'e zo BY/word-bu) is a capital/capitalised/upper-shift letter/digit/symbol in alphabet/character-set x2 representing x3.
to'a zei lerfu
x1 (la'e zo BY/word-bu) is a lower-case letter/digit/symbol in alphabet/character-set x2 representing x3.