[BJH]

I read with interest that someone said that 'r' does not involve the tongue touching teeth at all - not quite correct. I have been teaching English and English phonetics for many years both in Japan and Australia, and I have found some misunderstandings about 'r' and 'l' pronunciation, especially as instructed to Japanese.
The English 'l' is the same as the Japanese 'r' as both involve the tongue touching the roof of the mouth. English 'r' as a standalone sound does not involve the tongue touching the teeth, HOWEVER when the 'r' is at the front of a word as in 'red' then the the tongue touches either the top left or top right rear molar tooth. The pressure must be slight or else the sound will distort. 'R' in the centre of a word is the same, especially if it is at the start of a syllable. At the end of a word it is the same as in the standalone situation.