Welcome to the site! Latin, like English and I presume most other languages, has quite a few words to indicate talking. In the context of "to speak a language" (which, by the way, doesn't work with "talk"), the most common form is the verb loqui. This is the infinitive form, equivalent to the English "to speak" as in "I want to speak Latin." That sentence would be Latine loqui volo.
Loqui is also the normal word for to converse. So if I wanted to say, "I am talking with you," you could say, tecum loquor.
The verb dicere is chiefly used of saying things. So to say a word would be verbum dicere.
Note that if you wanted to use loqui in a particular way, it conjugates similarly to a passive verb, yet is active in meaning. To see the full paradigm, check out the charts on Wiktionary: loquor.