Kurdish Speakers?

One aspect of the debate that has always confused me is the issue of Kurdish speakers. My (correct?) understanding is that Iraq has a large Kurdish population which does not speak Arabic and/or is unlikely to participate in a survey conducted by a non-Kurdish speaker. References welcome! Lancet II reports that all the interviewers spoke English and Arabic. It does not mention Kurdish. Does this mean that none of the interviewers spoke Kurdish? That is what I would expect. Does that matter?

Consider the trouble that the ICLS went through to translate its survey into both Arabic and Kurdish.

The questionnaires reflect the nature of the survey. Two questionnaires were used: one general questionnaire for each household, answered by the household head or a member of the household with knowledge of all members was the respondent; and one targeted questionnaire used to interview women of the household aged between 15 and 54 years. The first questionnaire dealt with housing and infrastructure, household economy, basic demography, and the education, health, and labour force characteristics of the household members; the second focused on the women’s reproductive history and children’s health.

Three versions of the questionnaires—one Arabic and two Kurdish—were used in the field.. Although the questionnaires were developed in English, they were translated twice—once into Arabic or Kurdish, then back again into English—in order to verify the translations and ensure that all members of the survey team had a common understanding.

Compared to many surveys, the questionnaires were quite long, with a median interviewing time of 83 minutes. Fifty percent of the interviews lasted between 60 and 105.

Either ICLS wasted a lot of time and money unnecessarily translating the survey into Kurdish or there is no way that Lancet II got a 98% response rate without using Kurdish speakers. Or is there a third possibility?