Ranked by: number of candidates
1.
Family (7604 candidates)
2.
Definite articles: de / het (5281 candidates)
3.
Question words (5158 candidates) 
4.
Colours (3676 candidates)
5.
Babies 1 (2990 candidates) 
6.
False friends : maken / doen (2437 candidates) 
7.
Fruits (2333 candidates) 
8.
Dialogue : Looking for a job (901 candidates) 
9.
Infinitive (891 candidates) 
10.
Animals(1) - sounds (808 candidates)
11.
King Albert II (681 candidates)
12.
Diminutive words (523 candidates) 
13.
Paronyms (521 candidates) 

14.
Snowman (269 candidates) 
15.
Mathilde, Queen of Belgium (264 candidates)
16.
Philippe, King of Belgium (189 candidates)
17.
Queen Paola (101 candidates)

