Table 2.

Questions which can be used to probe various factors of language experience in survey design.

Factor of Interest	Categorical Questions (Useful for Recruitment)	Open-Ended/Gradient Questions (Useful for Survey Design/Capturing Continuous or Qualitative Differences)
Age and Order of Acquisition	Did you start learning [Language X] before [Age Y]	At what age did you begin learning [Language X]?
	Is [Language X] (one of) your first language(s)?	Consider probing How long was [Language X] used before exposure to another language?
Context of Acquisition	Did you grow up speaking [Language X] in [Region Z]?	Please list the locations you have lived in, the ages you lived there and the languages you spoke during that time.
	Did you grow up speaking [Language X] at home/in school?	What percentage of the time did you speak/hear [Language X] with your family growing up?
	Were you exposed to [Language X] at home/in school?	How many years were you exposed to [Language X] at home/in school?
	Was [Language X] the language of instruction in school?	How many years was [Language X] the language of instruction at school?
		Consider probing Presence of and/or interaction with [Language X]-speaking community networks
		Interest in [Language X] media
Language Proficiency/Usage Practices	Can you speak/read [Language X]? / Are you a (fluent) [Language X] speaker? / Are you comfortable speaking [Language X]?	Please rate on a scale of 1–7 your proficiency/fluency/comfort in [speaking/understanding/reading/writing; Language X].
	Do you mainly use [Language X] (at home/at work/in daily life)?	What percentage of the time do you speak/hear [Language X] at home/work/school/with friends?
		Consider probing
		Language use in different spheres (e.g., home, work, and school)
		Literacy
		Which language varieties they use
Language Identity/Allegiance	Are you a [Language X] speaker?	Please rate on a scale of 1–7 how much you agree with the following statements: “[Language X] is my [native language/Mother Tongue/etc.]”
	Do you consider yourself a [Language X] speaker?	“[Language X] is my preferred language”
	Do you consider [Language X] to be your? [contextually relevant term, e.g., native language, Mother Tongue]?	“I feel a strong connection to [Language X]”
		Consider probing
		Feelings or perceptions of pride, value, community, and nationality related to using or learning [Language X]