The best advice I can give to a subtitler when they start translating to and from English or Spanish is to translate for meaning rather than to translate words.
The key is to pay attention to what someone is saying and not just the words they are using. The most comical and absolutely awkward subtitles are those which have been translated literally, eg: ‘A otro perro con ese hueso’ as ‘ To another dog with this bone’. This expression means ‘you’re pulling my leg’ in English and it cannot be translated literally.
Do not confuse this with the register. Always need to be faithful to the original. Emulate the original style. It may sound obvious, but translators often slip up here. It is important not to change the tone of the character or re-write the script. You need to copy the tone and register.
Know your audience and think about what your objective and aims are for the translation. Think about what the original content is intended for and serve the translation in this way. Familiarize yourself with the topic of speech.
Translation tip (EN/ES)!
In English, it is common to make verbal periphrasis with “can/could” and of course you can literally translate them into English but you have to take into account its usage is far less common in Spanish.
This is a very important translation rule, just because there is an equivalent doesn’t mean you have to use it. You need to take usage frequency into consideration and in the subtitling as you have to measure your words very carefully. So when translating EN>ES it plays in our favour to drop modals at times.
Check out GOSUB and Natives For You e-book on English and Spanish subtitling: