This pattern is written in US terms in English and uses worsted weight yarn with a 3.25mm hook (or whatever hook you’re comfortable using with the yarn you have chosen).

Materials:
Approx. 40 yards/ 17 grams of worsted weight yarn in body color
Approx. less than 2 yards/ less than 1 gram of worsted weight yarn in tongue color
18 or 20mm safety eyes
3.25mm crochet hook
Stitch marker
Poly-Fil
Scissors
Tapestry needle

Finished measurement : approx. 4.5 inches