English words that are difficult to pronounce for foreigners include height, subtle, queue, fruit and colonel. Words that are commonly confused for one another include accept and except, there and their, principle and principal, affect and effect, and assure and ensure.
Height, subtle and fruit are all difficult to pronounce because they each have a letter that is not pronounced. Queue is even more difficult, as pronouncing it correctly is done by only reading the first letter. Colonel is pronounced kernel, which is very different than its spelling.
Words that sound similar but have different meanings are often confused for one another. Accept means to agree or receive, while except excludes something. There refers to a place and is an adverb, while their is a pronoun used when multiple people or things possess something. Principle refers to a value, while principal typically refers to the head of a school but can also simply mean the main thing in a group.
Affect is a verb, and effect is a noun. Assure is making a person confident in something or removing his doubts about it. Ensure is taking action to be certain something happens. Insure is sometimes also confused with assure and ensure. Insure refers to business transactions, specifically covering something with a policy through an insurance company.