Originally Posted by: bisaiya87

I'm learning the C Embellishments lesson. I wonder is it Csus2 and Csus4 ? Not Cadd9 or Cadd11 like in the lesson ?

Those are interchangable. The 9th scale degree is the 2nd scale degree an octave higher. The 11th is the 4th an octave higher.

Strictly speaking the 9th & 11th do refer to the notes of the scale in a higher octave. But from a practical perspective they are often used interchangably in guitar practice.

Hope that helps!