The words for "my", "your", "his", etc, can appear with the genitive or possessive case. Examples for the first declension, a group of nouns all of which are masculine, are:
leabhar mo mhic (LOU-uhr muh VIK), my son's book ("the son's book" would be "leabhar an mhic" (uh VIK).
ceannár mboird (kyoun aw*r MWIRD), head of our table ("head of the table" would be "ceann an bhoird"(uh VWIRD).
The words "mo", "do", and "a" meaning "his", all aspirate initial consonants in the following word.
The word "a" meaning "hers" does not change the initial consonant in the following word, but causes "h" to go before an initial vowel.
The words "ár"; "bhur" (vwoor), your (plural); "a" meaning "theirs", all eclipse initial consonants in the following word, and cause "n" to precede an initial consonant.
With a term like "os comhair" (ohs KOH-ir), before, in front of, an expression like: os comhair an chairr (uh K*AHR), in front of the car, is easy to understand. If you wish to say "in front of me" in Irish, however, you must say: os mo chomhair (ohs muh K*OH-ir). In this, the word for "my" modifies the noun "comhair". This form is necessary because Irish has no word for "of me" or "mine", only for "my".
Other examples of this:osár gcionn (ohs aw*r GYOON), above us
i m'aice (i-MAK-e), near me
inár n-aice (in aw*r NAK-e), near us
ina láthair (in uh LAW*-hir), in their presence (also "in his presence" and "in her presence"; the context or other words in the sentence tell you which is the meaning)