I am open to learning.... That one is correct. You can't say the other one because it is WRONG! I recommend you master basic English sentences before you go on to the more difficult ones, because you are making a complete mess of them. Here is a basic rule to remember: A preposition is followed always by the GERUND. Master a simple rule like that and you won't have too many problems.

Hi there. Yes, "learning" is the gerund of "to learn". In this case, because it is a feeling toward something, you could also use the infinite "to learn". Both of these mean the "act of learning". For example: I like to learn = I like learning I hate to play golf = I hate playing golf. I am open to learn other languages = I am open to learning other languages but "to learn" (infinitive) doesn't always equal (gerund) "learning", for example I want to learn (correct) I want learning (incorrect) You can usually use the gerund or the infinitive when it is a personal attitude toward something. There may be other situations as well, so watch how natives use it.

This is a really difficult point in English. There are verbs that only take gerunds (for example, "enjoy swimming"), verbs that only take infinitives ("decide to quit"), and verbs that take both (like swimming / like to swim). And some verbs take both but the meaning changes. For example, "I stopped smoking" (I do not smoke anymore) vs. "I stopped to smoke" (I took a break and smoked a cigarette). The same is true for expressions with adjectives and prepositions. Many of these only take gerunds: be interested in, look forward to, be open to, etc. The bad news is there are no specific rules and you have to memorize all of these. ;(

Get used to doing, be used to doing, look forward to doing, etc.

Yes, really, it’s a difficult task for this kind of the Gerund. So maybe we must keep in mind that the Gerund is not a verb in these constructions. We can see what the native ones talk: A pragmatic approach to training programmers. Secrets to training the perfect dog. Beginner’s guide to playing the harmonica. He is closer to playing in game Wednesday. Next task: Getting back to playing golf. Introduction to reading music. I’m looking forward to seeing this film. I finally got around to seeing Art. Tom says no to seeing some puppies. Is there any connection to seeing ghosts? Do you have any secret to speaking English fast?