Is the infinitive form of verb a true verb?

Question

My question is just as mentioned in the title of this post: Would you call an infinitive verb a true verb?

I can't find any direct mention of it anywhere on the web. The CMoS (2010) catalogs Infinitives under Verbs and defines it as follows:

An infinitive verb, also called the verb's root or stem, is a verb that in its principal uninflected form may be preceded by to {to dance} {to dive}.

However, chompchomp.com mentions this about infinitive verbs:

An infinitive will almost always begin with to followed by the simple form of the verb, like this:

To + Verb = Infinitive

Important Note: Because an infinitive is not a verb, you cannot add s, es, ed, or ing to the end. Ever!

Answer 1

In other languages, the full infinitive is the base form of the verb, but in English, we use the bare infinitive.

Spanish, French, Italian, German and others use a full infinitive as the base form of the verb from which to conjugate whereas in English, because the full infinitive has two words instead of one, we use what is called the BARE infinitive to conjugate verbs. For example:

Speak- I speak, you speak, he speakS, we speak, they speak.

The only form of the bare infinitive that changes for REGULAR verbs in the present is the third person singular.