What do you thing about it? It is better to talk about professional subject like advertising for exemple or do grammatic exercices to learn english?
As someone whose first language is English, grew up speaking Cantonese in the house, learned French in French immersion school throughout elementary and high school, and learned (and I use the term loosely) Spanish as an adult, as well as having spoken extensively to several eminent linguists about language acquisition, I would say that it takes a combination of both to learn any language, especially as an adult. As a child, common grammatical structures are learned, by and large, without formal instruction (thus the number of native speakers who speak and write fluently, but don't have even a rudimentary formal understanding of the language). Adults, however, often require formal training in order to acquire the same skills. BTW, I have to commend your English, ernest. I learned French and spoke it daily from the age of 10 to the age of 18, and it is definitely inferior to your present English. It also takes some serious gonads to talk about your language difficulties on this forum, where you have been the subject (often rightly, imo) of ridicule on more than one occasion.