-m-

• -ng- – Default interfix for compounds with preceding stem ending in a vowel.
• -n- – for compounds with preceding stem ending in a vowel, but next stem starts with the letter (d), (l), (r), (s), or (t).
• -g- – for compounds with preceding stem ending with letter (n).

From -ng (“enclitic suffix”).

-m-

1. Compound interfix, connecting the adjective stem to the noun stem, after the preceding stem ends in a vowel and where the next stem starts with the letter (b) or (p).

   Synonyms: -ng-, -g-, na, -ng, -g

   ‎haba + ‎-m- + ‎buhay → ‎habambuhay

   ‎ganti + ‎-m- + ‎pala → ‎gantimpala

   ‎bago + ‎-m- + ‎bayan → ‎Bagumbayan

• Tagalog terms interfixed with -m-