Or Siobhan St. John Cholmondley
(Shevorn Sinjun Chumley)
Most of the phonemes of Japanese are readily pronouncable by English speakers.
Japanese is syllabic in nature, with all of the syllables taking the form of consonant plus vowel.
however, as is usual with natural language there is some jiggery pokery to this pattern. The 'T' plus vowel list looks like this:
The 'Tsu' is a has a consonant cluster in violation of the basic syllable pattern.
English speakers often have trouble pronouncing this consonant cluster at the start of a word.
The well know word Tsunami is often pronounced Sunami.
You might be told that a place name is つどがわ 'Tsudogawa' but English speakers will often have no clue whether it is 'Tsudogawa' or 'Sudogawa'.
Japanese also has another violation of the 'consonant plus vowel' syllable pattern.
Due to borrowings from Chinese, a 'y' can be inserted into the syllable.
こ is pronounced 'ko' (as in 'cop') but inserting a small version of the character よ (yo as in yoghurt) gives きょ 'kyo'.
English speakers often struggle with this, pronouncing 京都 きょうと（Kyoto) as きようと (Kihyoto) (Notice the difference in size of the second character.
Thus Tokyo become Tokiyo, with an extra syllable.
Another problem for English speakers of Japanese is vowel sequencing.
English makes liberal use of the schwa sound in multi-syllable words.
Even though the spelling has three 'a's', the word 'banana' is actually pronounced 'bunanuh'. The first and last vowels do not have the same pronunciation as the middle vowel.
In the word 'Japan' the first vowel is a schwa and the second vowel is an pure 'a'. (Juhpan)
However in the word 'Japanese' the schwa has moved downstream and is now in the second syllable. (Japuhnese).
English basically hates to repeat the short vowel a, alternating adjacent syllables with schwa.
Japan is Juhpan.
Banana is buhnanuh
Caravan is Caruhvan
This causes English speakers to drawl away in Japanese trying to recreate the schwa/vowel alternate pattern in multi-syllable words.
暖かかった ('It was hot') is pronounced 'ATATAKAKATTA by Japanese speakers, each 'a' sound exactly the same as the other a's.
English speakers tend to drawl it into a more sing-song rhythm with alternate vowels and schwas, which sounds very 'English' to the Japanese ear, as gross a violation as 'Flied Lice' sounds to the English ear.
Edit for typo