Question

what are 6 classes in Spanish that are cognates?

Answer 1

When you're learning a new language, a cognate is an easy word to remember because it looks and means the same thing as a word you already know. For example, gratitude in English means the same as gratitud in Spanish.
In fact, there are 7:
1. International vocables: created by all of languages during the development of humanity knowledge and they are based on Latin language. Here you can find: people names, institutions, geografic concepts, etc., because they have little modifications between languages generally.
2. Romanic words: This is Roman vocabulary specifically. Knowing this root language, you can understand the words based in it.
3. Phonetic or sound correspondences: they permit to identify the 'kinship' between letters in words in different languages.
4. Graphs and pronunciation: In Romanic languages (as Spanish), same letters are used to transcript most of sounds, but sometimes you can find different 'orthographic solutions' that can difficult to recognize the similarity of the words.
5. Identical syntactic structures: This kind of languages have 9 different types of basic sentences, identical in structure.
6. Morpho-syntactic elements: These allow you to recognize different gramatical categories.
7. Prefixes and suffixes: If you can recognize and separate them of the rest of a word and understand them, you can reach to understand the entire word.

Maybe, these easy rules can help:
1. Perfect cognates
2. Near perfect cognates
3. English nouns ending in -ary, can be replaced for -ario in Spanish.
4. English adjectives ending in -ic can be converted to Spanish with -ico ending
5. Same with -ous English adjectives to -oso Spanish adjectives.
6. And -ct English nouns to -ecto Spanish ending.

But there are a lot of examples. Maybe these sites can help: http://www.realfastspanish.com/vocabulary/spanish-cognates
http://www.linguasorb.com/spanish/cognates/
And this interesting site:
http://projectsharetexas.org/resource/cognates-english-1-reading