Cognates
Cognates are words in two languages that share a common origin and therefore look and/or sound similar and usually share meaning — for example English "information" and Spanish "información" — and they are one of the fastest on-ramps to vocabulary in a new language.
English shares an unusually large number of cognates with Spanish, Portuguese, and French because roughly 30% of English vocabulary derives from Latin (often via French), the same source as most Romance-language vocabulary. Words ending in "-tion", "-sion", "-ty", and "-ism" are especially reliable cognates.
For Spanish and Portuguese speakers learning English, recognising cognates can unlock a working vocabulary of several thousand words almost immediately — the challenge is usually pronunciation and register (many English cognates are formal/Latinate, so the everyday equivalent is often a shorter Germanic word instead, like "start" versus "commence").
"False friends" — words that look like cognates but have diverged in meaning (English "actually" vs. Spanish "actualmente", which means "currently") — are the main trap. Comprehensible input helps here too: hearing a word used correctly in context corrects a false-cognate assumption faster than a rule ever could.