"Mes filles comprennent la lettre."
Translation:My daughters understand the letter.
Because the reference to girls is "3rd person plural". I've found the following patterns seem to apply.
1st person -e
2nd person -s
3rd person -e
1st person -ons;
2nd person -ez;
3rd person -ent
1st person (i: je) mange
2nd person (you: tu) mange-s
3rd person (he, she: il, elle) mange
1st person (we: nous) mange-ons;
2nd person (you: vous) mange-z;
3rd person (they: ils, elles) mange-nt
What if you were coaching a girl's football team and you wanted to say in a familiar way that the girls on the team understand the game? In English you would say "my girls understand the game." is there a way to express a possessive relationship without the meaning changing to "daughter?"