The language intervention 'Kaatje Klank' is designed for stimulating the speech production and speech perception skills of 4-year-olds in an early childhood educational setting, in order to stimulate early literacy skills. These skills are crucial skills for technical reading in later ages. Good reading skills are an important condition for academic success.

To measure the effect of the language intervention 'Kaatje Klank', the intervention will be applied in six Dutch preschool classes (n = 100 children, 50% native speakers of Dutch, 50% non-native speakers) during 12 weeks (daily). Teachers will be trained and observed using a coaching trajectory.To measure the effect on speech production and perception skills, a pre- and posttest and a comparison with a matched control group (n = 100 children, 50% native speakers of Dutch, 50% non-native speakers) will be used. The control group will receive a different language intervention which focuses on vocabulary development (World-project).

Inclusion Criteria:

• In eary childhood education in Flanders (2de kleuterklas)

Exclusion Criteria:

• Language or speech disorder
• Less than 1 year acquiring Dutch