P Suski 
The Phonetics of Japanese Language [PDF ebook] 
With Reference to Japanese Script

This book gives true characters of Japanese speech sounds in reference to European speech sounds. When it was first published in 1931, it was the first book of its kind. There are only 5 Japanese vowel elements as opposed to 18 in English, 13 in French and 8 in German. There are 15 Japanese consonants, 26 in English, 22 in French & 23 in German. Because of the lesser number of elements, it follows that the wider range in vowels and consonants is heard by Japanese ears, so this volume gives average sounds uttered by Japanese in the twentieth century in relation to the English sounds.