There is strong evidence to support the claim that English is a difficult language to learn. English has a crazy spelling system and it seems like every word makes up its own pronunciation rules, because English has borrowed so many words from other languages. In order to know how to read the spelling you have to know which language it comes from or have previously heard the correct pronunciation.
Irregular verbs in English are seemingly complex and are often a headache for English language learners. Why is the past tense of “buy” “bought”, and why is the past tense of “sell” “sold.” Why aren’t “buyed” nor “selled” real words?
In English, questions are made by changing the order of the words, something that doesn’t exist in other languages like Portuguese. Many Brazilians will say “You are American?” instead of the correct “Are you American?” Word order is not only important when asking questions, but when describing nouns as well. English has very subtle word ordering rules that make “A cute little brown dog” correct to say, whereas “A brown cute little dog” would be incorrect.