Singing elocution tricks or Stone in Love with Oooooo

One of my many favorite songs, The Stylistic’s Stone in Love with You, sudden fell out of my top 20. This is because the lead singer never, ever says ‘you’. He leaves off the ‘y’ every single time and it became annoying. Since then I’ve noticed this in other songs. Never as bad as in Stone but there.

When I was in Glee Club many, many (many, many, many) years ago, the teacher gave us what she called ‘elocution tricks’, none of which I remember exactly but I do remember them being mostly about hard sounds and not vowels.

Is that ‘ooo’ thing an individual singer’s tic or purposely done? Does anyone know what I’m talking about with these ‘elocution tricks’?