plural form: americans, britishs,spanishs

[brend10]

Can you please make them plural as in the example;

Americans are taking more vitamins than ever before in history.

American: single... americans: plural

what about British?

Britishs are.... or Britishes are
Spanishs are ... or Spanishes are

 

[Horsa]

British and Spanish are adjectives and so don't have plural forms.

The correct terms are Britons and Spaniards.

Briton(s) is often informally shortened to Brit(s).

Hope that helps

 

[Offroad]

yeah, American is an adjective, however, people say and write:

Americans are the richest people in the world.

and so on.

 

[Englishlanguage]

yeah, American is an adjective, however, people say and write:

Americans are the richest people in the world.

and so on.

Adjective are often used to refer to a people (i.e. the French, the British). However, in some cases (according to the rule when adjectives do NOT end with ch, s, sh or z, but the most common cases are adjective ending with -an), an s must be added to the adjective to form the word which refers to the people.
i.e.
Canadian => Canadians
Argentian => Argentinians
American => Americans
Italian => Italians

This is the source (Look at paragraph 2c).

 

[Horsa]

Yes but American, Canadian, etc are also nouns - it is just that their form coincides with the adjective.