Help with verb forms

[Lister]

I am currently doing an error analysis on the English of a native speaker of French. Her vocabulary is excellent, and she uses appropriate verbs, but frequently applies an incorrect verb form to the pronoun that she has chosen e.g. "He understand more."

When I add "s" to the end of a verb, such as "understand" changing it to "understands", what exactly have I just done?
What is this new verb form called?

Thanks for your help.

Lister

[SakuraGirl]

Dear Lister,
Hopefully, this will make sence!
In this case, the verb "understand" is in the simple present form. When using the simple present form in 3rd person singular (he, she, it), you must add "s" (or "es" ) to the verb.

Examples:

First person singular: (No "s" is needed)
"I understand more."
or
"I do more."

Second person singular: (No "s" is needed)
"You understand more."
or
"You do more."

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Third person singular: ("s" is needed)
"He/she/it understands more."
or
"He/she/it does more."
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Hope that helps!
-Erica