I've written about how I learned to speak, read, and write Japanese, Mandarin, and Spanish. I've also covered my experiments with German, Indonesian, Arabic, Norwegian, Turkish, and perhaps a dozen others. There are only few language learners who dazzle me, and Benny Lewis is one of them.
Cognates are “true friends” of words you recognize from your native language that mean the same thing in another language.
Words like Action, nation, precipitation, solution, frustration, and thousands of other -tion words are spelled exactly the same in French, and you can quickly get used to the different pronunciation. Change that -tion to a -ción and you have the same words in Spanish. Italian is -zione and Portuguese is -ção.
Many languages also have words that share a common (Greek/Latin or other) root.
Even languages as different as Japanese can have heaps of very familiar vocabulary.
The older you get the more difficult it is to learn to speak French like a Parisian. But no one knows exactly what the cutoff point is-at what age it becomes harder, for instance, to pick up noun-verb agreements in a new language.
There are many examples of people who pick up a language later in life. Our ability to learn new vocabulary appears to remain constant, but most of us will not be able to master grammar like a native speaker.