What part of speech are the words to change?

Answer 1

"To change" is an infinitive, which means it specifies the action, or verb, without ever stating the subject. For instance, with "to change," we are being told something is changing without being ever told what is being changed

For this reason, we don't usually keep verbs in their infinitive form, but we conjugate them to fit the subject and tense, such as: "I changed, they are changing it, they will change."

However, exceptions for keeping an infinitive intact in the sentence would be when the infinitive is the subject or an object and not the actual verb. As a subject, "To change is sometimes scary" or as an object, "I didn't want to change."

Answer 2

The words "to" and "change" can each function as different parts of speech depending on the context. "To" can be a preposition, infinitive marker, or an adverb. "Change" can be a noun or a verb.