The bilingual language experience calculator

The online questionnaire below had to be disabled due to issues with the access permissions required to view the results.  A new online tool is being designed as part of our Quantifying Bilingual Experience project.


The calculator is based on a parental questionnaire intended for children who are exposed to two languages: the language of schooling (assuming schooling in one language only) and a “home language” (the language of one or both of their parents).

Once the questionnaire is filled in (see link below), the bilingual experience of the child is automatically calculated, and expressed as four estimates of his/her experience in the home language:

  • current input (averaged over a year), expressed as a percentage
  • current output (averaged over a year), expressed as a percentage
  • cumulative input (over their lifespan), expressed both as a percentage and as the number of full-months equivalent
  • cumulative output (over their lifespan), expressed both as a percentage and as the number of full-months equivalent

“input” corresponds to the child’s exposure to the home language (i.e. being addressed in that language)

“output” corresponds to the child’s use of the home language (i.e. addressing others in that language)

The procedure for calculating each of these measures is explained at the bottom of this page.  It is based on a simplified version of Unsworth’s UBiLEC.[1]


Samira is 8 years old.  She speaks Arabic with her mother and grandmother, and English with her father.  She has two siblings, with whom she speaks Arabic and English, approximately to an equal amount.  Every year, she spends a month in Morocco, where she speaks and hears only Arabic.  She has been exposed to Arabic and English since birth.

  • Her current input in Arabic is 77% (so her current input in English is 23%): at the moment, she receives more input in Arabic than in English.
  • Her current output in Arabic is 62% (so her current output in English is 38%): at the moment, she speaks in Arabic more than in English.
  • Her cumulative input in Arabic is 85% (equivalent to 82 months of full exposure, as she is 97 months old).  That means she had more exposure to Arabic than English over her lifetime so far.
  • Her cumulative output in Arabic 72% (equivalent to 70 months of full use. As she is 97 months old). That means she has been more productive in Arabic than in English over her lifetime so far.



We are sorry but this is no longer available as on online tool.  The paper version of the questionnaire can be downloaded here



Current measures of language input and output are calculated as follows. The total number of hours of interaction with the child per year is calculated for each of the child’s interlocutors. The proportion of total input received by the child from each interlocutor in the home language is calculated as the total number of hours of interaction with that interlocutor, multiplied by the proportion of the time the home language was used with that interlocutor (if a child is interacting with more than one person at a given time, the measures are divided by the number of interlocutors). By adding these proportions from all the child’s interlocutors and dividing the sum by the total number of hours of interaction, we obtain a measure of current input in the home language for that child, expressed as a proportion of their total interaction time (assumed to equate to waking hours). Current input in English is calculated in the same way. The sum of current input in the home language and in English comes to 100%. The same procedure is repeated for output.

Cumulative measures of input and output in the home language are calculated as the sum of (i) the number of months of monolingual exposure (i.e. prior to onset of exposure to English — this amounts to 0 for simultaneous bilingual children and for monolingual children) and (ii) the number of months of bilingual exposure multiplied by the proportion of current input (or output) in the home language. The cumulative measures thus correspond to the total number of month-equivalent of full-time exposure to the home language.

[1] Unsworth, S. (2013). Assessing the role of current and cumulative exposure in simultaneous bilingual acquisition: The case of Dutch gender. Bilingualism: Language and Cognition, 16, 86-110.