Think of the sentence "You are not a child."
If you are a child you might say (in English) "Yes, I am a child."
In English, you emphasize the word "am" to contradict what the other person said.
In Dutch, the word "wel" serves this purpose.
Think of it as the exact opposite of the word "not" ("niet" in Dutch)
Apparently English "well", Dutch "wel", German "wohl", and variants of "vel" in the languages originating from Old Norse all come from the Proto-Germanic word "wela" ("in a good manner; well"):
It works to use English "well" as an intensifier in some situations too:
"It is well understood what must be done." "We are well aware of the difficulty here." "She is well ahead of you at this point."
And it's used a bit more liberally in slang around the British Isles:
"That match was well rough." "You're well out of order." And I can't not link Catherine Tate: http://youtu.be/qSNK-9v7_JI
As far as I know, that's as far as we take it anymore in English. But I would say it's still enough part of our vocabulary that it doesn't sound TOTALLY bizarre to hear "Yes, I am well a child." It's not correct, but I think most people would understand and accept the usage of "well" as an intensifier.
Does "wel" work like "wohl" does in German (or at least in some western regiolects of German)? In this instance it seems like it, but "wohl" can also be used differently, e.g. as in "Kannst du mir wohl das Wasser reichen?" ("Could you give me the water (please)?"), or in some other cases in place of "doch".
Check out the grammar explanation by the course creators regarding "The Dutch Alphabet & Pronunciation":
Very simply put it is somewhere in between an English "w" and an English "v" (but it's pronounced like, well, a Dutch "w", not like a Dutch "v").
There might actually be an identical kind of adverb in English. e.g. ''I don't think he understands.'' Reply:''No, I think he does (understand). Dutch translation: Ik denk niet dat hij het begrijpt. Reply:Nee, ik denk dat hij het wel begrijpt. The difference between English ''do'' and Dutch ''wel'' is that you can't use ''do'' in front of a form of TO BE, as far as I know. However, if it were correct usage to do so, you would translate the above phrase as ''Yes, I do am a child''--''Ja, ik ben wel een kind.'' One more: I'm not very knowledgeable about video games but I do know they're a lot of fun.-->Ik weet niet veel van videospelletjes maar ik weet wel dat ze erg plezierig zijn.
See Kai_E.'s comment above: In this sentence, "wel" is used not so much for emphasis, but rather to contrast a negative statement. Consequently, you should use "wel" in this way if you want to do just that. ("Wel" seems to have some further uses, but you should usually be able to tell its function from context once you've learned the different possibilities.)