I am trying to guide my son on how to create flashcards to study vocabulary for Spanish as a second language. My question is about english though. When I learned english long time ago I used 'to' to indicate that the word is a verb. So, I would write 'to go', 'to be', etc instead of 'go' or 'be'.
Is there still any reason why I should use 'to go' instead of 'go' or is it just that long time ago people were more formal? My son asked me and I don't have a good answer.
In English, the infinitive of a verb, which is the "basic" form, is usually preceded by "to"; this is called the full infinitive or the to infinitive. Without the "to", and standing on its own, it's called the bare infinitive or the base verb.
Using "to" or not doesn't have anything to do with formality. It does make it clearer that the word is a verb, though: consider the word seat. Without "to", it's not clear if you mean the verb to seat or just the noun seat. Since so many English words can function as both verbs and nouns, it's helpful to be completely clear about which one you're referring to.
Using "To verb" tells the reader you are using a verb when it would otherwise be unclear.
There is a lot of overlap between verbs and nouns in English. For instance, in your question, you use "answer" as a noun, but down here, I answer your question with answer as a verb.
Another example- I decided not to comment (verb) with a comment (noun).
In addition to well established examples like those, English allows speakers to make nouns into verbs by simply using them that way (verbing a noun).
"Go" is almost always used as a verb, but "To have a go at something," means to make an attempt at it.
While it would be most technically correct to translate ir as the infinitive "to go", I would say that putting the "to" on flashcards is not idiomatic in English. I recommend dropping the "to", because that's what a native English speaker would probably do.
The reasoning is probably clearer when you consider an analogy with nouns. Spanish flashcards would probably be labelled el chico and la chica. But English speakers would consider the definite article to be useless noise, because the gender hardly matters. English flashcards would just say "boy" or "girl".
Similarly, English verbs are just verbs. We don't have to learn whether the infinitive ends in -ar, -er, or -ir. Present-tense conjugation, for the most part, is simple and regular. There is therefore no point in learning the infinitive form preceded by "to" — unless that's how your brain prefers to learn it.
