君の手紙で私はうれしくなった。

you; buddy; pal; monarch; ruler; sovereign; (one's) master

indicates possessive; nominalizes verbs and adjectives; substitutes for "ga" in subordinate phrases; (at sentence-end, falling tone) indicates a confident conclusion; (at sentence-end) indicates emotional emphasis; (at sentence-end, rising tone) indicates question

letter

indicates location of action; at; in; indicates time of action; indicates means of action; cause of effect; by; and then; so; indicates continuing action; indicates certainty, emphasis, etc.

I; me; private affairs; personal matter; secrecy; selfishness

topic marker particle; indicates contrast with another option (stated or unstated); adds emphasis

happy; glad; pleasant

to become; to get; to grow; to be; to reach; to attain; to result in; to prove to be; to consist of; to be composed of; to succeed; to be complete; to change into; to be exchanged for; to play a role; to be promoted; to do ...