Sorry, I don't speak English.

This is interesting! I have heard that it is easier for younger children to pick up extra languages. I know a three year old who knows English, Chinese, and ASL. She is at a point where she doesn't always know what language to use with what company, so if she needs something she will ask for it in all three languages.
It is probably easier to understand native speakers if you learn the language by immersion, and thus can learn the proper pronunciation and be able to understand accents easier.

I am a native English speaker and in high school and in my freshman year of college I took Spanish. I found that Spanish was very easy to learn because of it's similarity to English. I can still put together sentences and remember most of the vocabulary a year and a half later! So the more similarity between the languages, the easier it is... just watch out for false cognates, like Billón (1,000,000,000,000) which is trilion in English!

I am also a native English speaker, and learned Spanish in high school for 3 years. I also found it was quite easy to learn the second language because of the similarities to English it has. I also realized in one of my classes how much more complex and difficult English is than Spanish because of words like to, two, too which all sound the same but have different meanings. Although I have a friend whose native language is English, and who took Spanish all of high school and into college also. She is now taking French also on top of that and finds it very difficult to not use some French in her Spanish writing and some Spanish in her French writing. I think it just all depends on the person, and also like you stated above the age too.

I am very impressed with people who are bilingual, I took three years of spanish in high school but I would not consider myself anywhere near fluent. Your statement about people believing that children may be confused while learning two or more languages may be true, but i recall from the book that people who are bilingual actually end up having better metalinguistic insight. That means they will be better aware of how language in general is structured and therefore used. Even if there is slight confusion or perhaps asking something in a few languages (as suggested in another comment) as a young child, the benefits in my opinion outweigh the potential confusion.

A lot of studies have shown that children who learn more then one language at an early age develop higher levels of cognitive ability. Besides the possible intelectual gains, its very useful for a child to know more then one language, both in youth and adulthood.

I find this topic very interesting. I have never really heard many people disagree with the theory that children learn languages better than older teens or adults. To me, it seems as if it would be difficult to learn two languages as a child because you wouldn't necessarily know which situation to use them in, but at the same time children can take in so much more information than adults can and they seem to learn a lot quicker. Also, I believe it would be easier for children to become involved with the other language they are learning because they have chances to study abroad in high school and college if they become good at that language. It is much more difficult for adults to find time in their schedules to visit another country and get the full effect of the language and culture.

I agree that children defiantly have the edge when it comes to learning languages. In fact I really wish my parents would have had me learning Spanish during my younger years. It is also very crucial to have real interactions and conversations with native speaker in order to truly learn a language. I find it interesting that you found French to be more difficult than English. English is quite random, especially with its tenses. There really aren’t any rules for it. Just to point out something in your blog that relates to this; in one sentence you used the word learnt for the past tense of learn. Yet, it is actually supposed to be learned. Although if we look at the word sleep, the past tense isn’t sleeped, it’s actually slept. I’m not criticizing your grammar at all, in fact I’m simply pointing that I would find English to be very difficult to learn if it wasn’t one’s native language.