Even though the word pairs below have similar roots, take a look at how only one word in each pair is a tsitsu word.
patinage / patin
Patinage is a tsitsu word.
Patin is not.
1. patinage (patsinage)
2. patin (patin)
matinée / matin
Matinée is a tsitsu word.
Matin is not.
1. matinée (matsinée)
2. matin (matin)
latine / latin
Latine is a tsitsu word.
Latin is not.
1. latine (latsine)
2. latin (latin)
In the number 1s, the t is followed by the vowel sound i. So the t is pronounced ts.
In the number 2s, the t is followed by the nasal vowel sound in. So the t is not pronounced ts.