What proportion of electors in Catalonia (those with the right to vote in the referendum) speak Catalan, Spanish or another language as their mother tongue?
The statistics I've found on mother tongue (referred to as "llengua inicial". Catalonia also collects statistics on what it calls "llengua habitual" and "llengua d'identificació") refer to the entire population of Catalonia. My question differs in two important respects. First, voters are 18 or over, and second, they must be Spanish citizens. It seems obvious to me that most immigrants living in Catalonia are unlikely to be native Catalan-speakers.
If there are no good statistics on my exact question, then reasonable inferences can be made from available information.