What are the five areas of phonology that make English hard to learn?

1. English vowel sounds - English has a large number of vowel phonemes, in particular a large number of dipthongs. These include some fairly rare phonemes that are difficult to distinguish for many non-native speakers.

2. Voiceless stops are fully aspirated, but so-called "voiced" stops are closer to unaspirated voiceless stops in many languages. This means that non-native speakers are liable to mishear b as p, t as d, etc.

3.English has a complicated stress rule which is not marked orthographically. Stress can also shift in derivation (like the way that record or refuse are stressed differently depending on whether they are verbs or nouns).

4.Some English consonant phonemes are rare, particularly the distinction between voiced and voiceless "th", and sh/zh. And the combination rules (eg. allowing Words like "strengths" and "visions") are less strict than many other languages

5. English stress patterns mean that unstressed syllables are frequently reduced (eg. the vowels become schwa). This can be difficult to imitate, especially when you're unsure where the stress is in the first place.