Spanish lyrics often say more with fewer words than English can. A single verb tells you who is singing, to whom, and how they feel about it, and a lot of the color lives in regional slang. Spanish and English are already set in the translator above, so paste the lyrics and you get two English versions: a faithful one that tells you exactly what each line says, and a singable one written to fit the same melody.
Spanish has more than one way to say you. Tú is close and casual, usted is formal or distant, and vos takes the place of tú in Argentina, Uruguay and much of Central America. English only has you, so a song that switches from tú to usted to sound cold, or to tease, loses that move. When the switch matters to the story, the notes point it out.
Spanish drops subject pronouns. Te extraño means I miss you without ever saying I. Adjectives show gender too, so estoy cansada tells you the singer is a woman, while the English I'm tired does not. The English has to pick a pronoun the original never spelled out, and when a line could go either way, the notes say which reading was chosen.
The same word can mean different things depending on where the song comes from. Guagua is a bus in the Caribbean and the Canary Islands but a baby in Chile, and urban Latin genres are full of street words you will not find in a dictionary. The translator reads regional vocabulary from Mexico, the Caribbean, Central and South America and Spain, and it explains the slang it had to interpret.
Spanish often rhymes on vowels alone, and so many words share the same endings that whole verses can rhyme without effort. English has far fewer matching endings. The singable version keeps rhymes on the same lines as the original, but it often lands on a near rhyme instead of a perfect one.
Spanish singers blend a vowel at the end of one word into the vowel that starts the next, so mi alma is sung as two syllables, not three. Count a line the way it is sung, not the way it is written, because that is the number of notes an English line has to fill.
Two original lines, written for this page, about someone who has not come home yet. Sung with the vowels blended, each line has 13 syllables and ends on a soft, unstressed syllable, which is typical of Spanish.
Me dejaste la luz del pasillo encendida,
y yo sigo esperando que vuelvas a casa.
You left the hallway light on for me,
and I'm still waiting for you to come home.
You left the light in the hallway, and it's still burning,
and I'm still waiting for you to come through the doorway.
The faithful version keeps for me, because me dejaste carries it. The singable version drops it to stay at 13 syllables, lets still burning do the work of encendida, and ends both lines on a soft syllable (burning, doorway) the way the Spanish does. Hallway and doorway also give the English an echo, standing in for the matching final vowels of the original.
Both. It reads lyrics from Mexico, the Caribbean, Central and South America and Spain, slang included. If a word means different things in different countries, the notes say which meaning it went with, so you can check it against where the song comes from.
Because Spanish keeps the subject inside the verb and English cannot. Duermo is I sleep, but duerme could be he sleeps, she sleeps or a formal you sleep. The translator picks the pronoun the rest of the song points to, and flags it in the notes when it is a real guess.
Spanish songs often mix in English words or whole lines. Anything already in English is kept as it is in both versions, and only the Spanish is translated.
That is what it is written for. Each line stays within about two syllables of the Spanish line and close to its stress pattern, and lines that rhyme in Spanish still rhyme in English. Sing it through once and fix any spot that feels crowded, since you know where the melody holds a note. If the song is not yours, releasing a cover with new lyrics may need permission from its writers or publisher.
Yes, that is one of the best uses for it. You get exactly one English line for each Spanish line, in the same order, so it lines up with the original timing. If the subtitles are going out publicly, have a fluent speaker read them once.