# Calculating Exposure to English

First of all, it is necessary to establish age of first exposure to English. For the purposes of this study, we determined age of first exposure as follows:

• When the child began to receive consistent and sustained exposure to English.

Most commonly, this was when the child began to attend an English-language daycare, preschool, or primary school program. Other possibilities include being cared for by an English-speaking babysitter for at least 3 days a week. The primary criterion is that the child is spending at least part-time (>= 3 days a week) immersed in a rich, English-only environment. Attending bilingual school is an acceptable environment, provided that the instruction is at least part-time (half) in English.

The following types of exposure to English are not counted:

• Casual infrequent exposure to English from television or in the community
• English spoken at home at the time of testing

This is because including these measures would make the calculation of exposure overly-complicated, and decrease the reliability and usefulness of the measure because of the increased variability. Furthermore, all the children in this study were exposed exclusively to their mother-tongue during infancy and toddlerhood, so considering casual English exposure was not necessary.

Note: If a child has a different history of exposure to English (for example: bilingual from birth or age of exposure much greater than 3 years), comparing that child to the norms given on this website may not be appropriate.

## Calculation Procedure for English Exposure

1. Convert age of exposure to months (multiply years by 12, and add months).
For example, age of exposure = 5;4 (years;months): 5x12=60, 60+4=64, age of exposure = 64 months
2. Convert age at test to months (follow same method as step 1.)
3. Subtract age of exposure from age at test.
For example, current age = 74 months, age of exposure = 64 months: 74-64=10, age of first exposure to English = 10 months
4. Adjust for any interruptions to the child's exposure to English greater than 6 months.
For example, if the family took an extended trip to the hope country, subtract these months from the child's total months of exposure to English.