1. You can find the BabyLex app on the app store (iPhone and iPad), as well as on Google Play for android devices.

2. Once the app has downloaded, open Babylex by clicking on the app.

3. If this is the first time ever that you are using the app continue with step 4. If you have already used the app and want to start a new test with a child you have already registered continue to step 7. If you have already used the app and want to look at past scores for a baby whom you completed previous tests with continue to step 14.

4. The first step is to create a record for your baby. To do this click on Test, then register new baby.

5. Then enter the name of your child. You can use a nickname if you want to – you do not need to enter the name of the child. This is merely so that you know which of your children a particular test relates to.

6. Next, you will be prompted to enter which language your child hears/speaks, the gender of the child and the birthdate of the child. Note that we do not store the information of the child’s birthdate. We merely use this to calculate the exact age of the child so that we can then provide a percentile score of your child’s vocabulary development compared to other child their age and their sex.

7. Click on Test.

8. You will now be prompted to choose the baby you want to complete a test with. Click on the baby you would like to complete the test with. If you have just registered a baby this will most likely be the baby you just registered. If you have used the app in the past with other babies, choose one of the babies to complete the test with.

9. Click on Start Test. Note that the next page now takes some time to load because the app is loading the information of all the data from all the children at the age of your child.

10. Once the page has loaded, you will be asked to answer yes or no for whether your child can say the word that appears on the screen. You will only have to provide a response for 25 words. It shouldtake you no longer than a couple of minutes.

11. Once you have completed the test, you will see the result informing you the number of words your child likely produces from the long version of the vocabulary questionnaire and also the percentile score of your child (see Interpretation of the results section). Note that this is merely an estimate provided by the app. It is not a clinical evaluation of your child’s language development. We are not doctors, we are researchers who are also parents and want to use our research to allow parents an insight into the development of their child. If you want a clinical evaluation of your child, please ask your paediatrician for contacts to the clinicians who can provide you such an evaluation.

12. You will then get a percentile score and the number of words approximately that the child speaks.

13. Click on Save result if you want to save this result or click on Discard if you want to discard these results.

14. If you click on Scores (later), you can later go see the scores for this baby.

15. In this early stage, please ensure that you write these results in a separate sheet so that you have access to this data in case the app is updated.

16. If you want, you can administer the babies section by deleting babies if needed, etc. Click on Edit, then on the red cross if you want to delete the data for a baby.