In the free introductory course we mentioned that there are many, many "cognate" or similar forms in moving between Spanish and English. Teléfono, vocabulario, masculino/feminino: these are all words that anyone who can read English would likely recognize with the correct meaning on seeing the Spanish word in writing.
There is a smaller section of cognate forms that do not have the expected or implied meaning, because the word wound up getting into the two languages via a different path or simply by the way it was used. We call these "false friends" (falsos amigos), and using them incorrectly in conversation can lead to... embarassment. Here's a few examples:
| Spanish word | Might Mean | Actually means |
|---|---|---|
| embarazada | embarassed | pregnant |
| tarde | tardy, late | evening (which does mean "late in the day") |
| zoológico | zoology | zoo |
Full list: There's a formidable listing of "falsos amigos" by Diego Marín in the Canadian Modern Language Review, Vol 37, No 1, October, 1980, pp 65-98 (paywalled).
Diacriticals are a fancy name for extra-letter markings, such as the acute accent (´) which, in Spanish, marks a syllable for emphasis, and other accent markings. In Spanish, it is important to note that 'n' and 'ñ' are actually two completely different letters, not the same letter with and without a diacritical. There's a separate section beginning with ñ in most Spanish dictionaries. Here's one example: año means year, whereas ano mean anus. Maybe all those crossword puzzle makers who use the clue "Spanish year" for ano... let's just say they can't tell their time from their tails.