Breakdown of O cão rasgou-me a manga do casaco.
de
of / from / by (means of transport) / wearing (attire)
o cão
the dog
o casaco
the coat
a
to / at (direction)
Questions & Answers about O cão rasgou-me a manga do casaco.
Why use -me here instead of saying rasgou a minha manga?
This is the dative of possession. In Portuguese, it is much more natural to use an indirect object pronoun (like me) to show who is affected by an action involving their own body parts, clothing, or personal items. It literally means the dog tore the sleeve 'to me'. While rasgou a minha manga is understood, native speakers strongly prefer rasgou-me a manga.
Since -me already shows it is my sleeve, why do we still need the article a in a manga?
Even though the indirect object pronoun me establishes whose sleeve it is, Portuguese still requires a definite article before the noun in these constructions. You are literally saying that the dog tore 'the' sleeve 'to me'. Dropping the a would make the sentence ungrammatical.
Why is the pronoun attached to the verb (rasgou-me) instead of coming before it?
In European Portuguese, the default position for object pronouns in affirmative main clauses is after the verb, attached with a hyphen. Since the subject O cão is a simple affirmative noun phrase and there are no 'magnet words' (like negative words, certain adverbs, or conjunctions) to pull the pronoun before the verb, it naturally attaches to the end.
If the dog tore someone else's jacket sleeve, how would this sentence change?
You would replace the first-person pronoun me with the third-person indirect object pronoun lhe. The sentence would become O cão rasgou-lhe a manga do casaco (The dog tore his or her jacket sleeve).