How to distinguish the spoken language and written language?

Today I was confused about the word, 'via' I have seen this word in many texts, but I have not heard in oral communication. I tried to search the word 'via' is used in spoken language, but I am not sure yet.

Is there any good way to distinguish the words are for the spoken language or written language? such as if I put a word on a website, the website shows me that the word is used in spoken or written language.

Thank you in advance.

Is there any good way to distinguish the words are for the spoken language or written language?

For the most part, every word that's used in written English is used in spoken English, and vice versa. If you see it in writing, then you can use it in speech, too, and vice versa.

The only exceptions I can think of are certain pieces of Internet slang which were created as abbreviations or emoticons rather than as words. Examples of this are "rofl" (an abbreviation of "rolling on the floor laughing") and "owo" (an emoticon; the "o"s are eyes and the "w" is a cat-like mouth). Although "rofl" and "owo" are common in colloquial Internet writing, they are extremely rare in speech.

Also, certain written words are used mostly for representing speech. For example, consider the following two written questions:

• What do you want to do?
• Whaddya wanna do?

The first version is the normal, common way to write this question. The second version is a special, unusual way of writing the question which indicates a fluent, relaxed way of pronouncing the question out loud.

The pronunciation indicated by writing "Whaddya wanna do?" is very common, but actually writing it that way is much less common.