Possessive comparative suffixes (-sa, -se, -sean, etc.)
I notice that when possessives are used in comparative sentences, the object(s) of the sentence have suffixes added to them. For example:
"Tá mo mhacsa níos sine ná do mhacsa." (My son is older than your son.)
"Tá mo chuidse gruaige níos faide ná do chuidse." (My portion of hair is long than your portion.)
"Tá níos mó peann aigesean." (He has more pens.)
"Tá níos mó leabhar aicise." (She has more books.)
How do I know what suffixes to use when? Is there a guide somewhere that can help me with this?
Update: Upon further research, it seems that the endings for nouns are the same as for the possessive adjectives (such as "liomsa", "leatsa", "a ceannsa", etc.). And the use of -sa or -se depends on whether the final vowel is slender or broad. Is that roughly correct?
Yes, whether you use the broad or slender ending depends on whether the word has a broad or slender ending.
You also have the ne/na contrastive for the first person plural:
tá níos mó againne.