- "Hablar" esta en tiempo infinitivo, que es la forma y modo verbal que expresa la acción del verbo, pero no la persona, el tiempo y el número y el verbo termina en: ar-er-ir ejemplo: comer, bailar, caminar, leer, barrer, correr. - Cuando usas ing or gerundio, la conjugación del verbo termina en : ando - iendo- Se emplea alguna forma del verbo "estar + ing" para dar un énfasis de algo que está ocurriendo en este momento. ejemplo: estoy comiendo, estoy caminando, estoy hablando.

The way I see it is this. The infinitive can be used as a noun. The present progressive form can not. Take the sentence "Seeing is believing". "Seeing" and "believing" are both being used as nouns. The Spanish translation would be "Ver es creer". One way to test this is to check if you can replace the -ing word with the English infinitive. So with your sentence "Speaking with you is fun", you can replace "Speaking" with the infinitive "to speak", as in "To speak with you is fun". Because of this you, you use the Spanish infinitive as in "Hablar contigo es divertido". You can see the other case in "I am speaking with you". If you used the English infinitive, you'd get 'I am to speak with you", which is completely different. So this is a present progressive sentence. To summarize, if you can replace the -ing word with the English infinitive, you need the Spanish infinitive. If you can't, you probably need the present progressive.

You use the present progressive when you're actually doing it...it's a bit different in English. But I've learned from studying Spanish that when you want to say something, you always have to be mindful of the IDEA that you want to communicate. Estoy hablando con mi mama sobre algo muy importante, asi que no puedo ir. - I'm talking to my mom about something very important, so I can't go. Hablar con mi mama es muy dificil porque ella nunca me entiende. - Talking with my mom is very difficult because she never understands me. Do you see the difference? Try and get out of translating things word for word...focus on ideas.

He's right. We only use the gerund, -ing, when we are doing something. That thing of making nouns out of verbs and adjectives, we don't do it. "Talking to you is fun", as a native Spanish speaker, that sounds really weird.