In English, all infinitives include the word 'to', e.g. to speak, to eat, to live.
However, Spanish has three verb types or conjugations. All Spanish infinitives end in -AR, -ER, or -IR, for example, hablar = to speak, comer = to eat and vivir = to live.
When you look a verb up in your Spanish-English dictionary you will find it listed in the infinitive.
In all likelihood, you will need to change the infinitive that you find in the dictionary to the part of the verb you wish to use (in grammatical terminology, you 'conjugate' the verb), e.g. hablar = to speak but hablo espaņol = I speak Spanish and mis padres hablaron con mi profesor de espaņol = my parents spoke to my Spanish teacher.