THERE ARE TWO TYPES OF -IR ENDING VERBS, IR-SST (ALSO KNOWN AS PACMAN) AND IR-ISS. EACH HAS ITS OWN PATTERN TO BE FOLLOWED.

WE WILL FIRST CONCENTRATE ON IR-SST (PACMAN).

There are only 6 verbs which are known as IR SST verbs, they are: SENTIR, PARTIR, DORMIR, SORTIR, MENTIR, SERVIR.  TO RECALL THESE, THINK OF : Some, People, Don’t, Sleep, Much, Sundays.

Not unlike other verb ending conjugation, one must also drop the IR. But in addition , BUT ONLY IN THE SINGULAR FORM, we must also drop the consonant which precedes the IR.   That means, you drop the T+IR or the M+IR or V+IR wherever it applies. That leaves us with the stems: SEN, PAR, DOR, SOR, MEN, SER and to those we add the new endings>>> S, S, T. we wind up with 1)SENS, 2)PARS ,3) DORT, 1)SORS, 2)MENS,3 SERT.

In the plural form those consonants return…. meaning that in the plural the stems are SENT, PART, DORM, SORT, MENT, SERV. AND to those we add the endings:  -ons, -ez, ent.

We will deal with ISS verbs at a later date.