-(t)ion suffix?

[googl]

Is there a -tion suffix in Engish? Or is it -ion? I found that we've got a -tion suffix in English, but it looks

calculate + ion -> calculation, calculate + tion -> calculatetion

awful. Or is is -ation: examine -> examination???

[Alan]

We would typically regard '-tion' as the suffix, but in many cases that which we are actually adding may be no more than the letters 'ion', and even then we may have to first omit a final 'e'.

It is wise not to expect too much predictability/regularity in English word-formation!