Want and querer in Spanish work similarly.
Quiero hablar con ella = I want to talk to her.
Spanish infinitives end in -ar, -er, or -ir. English ones begin with to with a few exceptions. Using want like this is not one of them.
Can is a modal verb. Here's all the common English modals:
can could will would shall should may might
English likes to use an additional word in front of the verb to change verbs (whereas Spanish would rather use a different type of conjugation or ending). The above words are examples of those.
Modals are special (versus auxillaries like have or be) in that they don't change at all according to plurality (you don't say He cans go to the park).
I can talk to her.
In English, you can replace can with be able to, which is not a modal verb.
I am able to talk to her.
This directly maps to Spanish poder
Puedo hablar con ella.
but if you're going to use the infinitive with can then you have to say be able to.