I wrote "Málo lidi potřebujou umět češtinu".
I used potřebujou because I thought 'few people' would require the 'they' conjugation. Are 'few people' considered a single unit for purposes of conjugating the verb?
Yes, from the point of view of Czech, the logic is the same as in "A group of people is doing something". Things like five, ten, few, several, many, etc. are all treated as "group", followed by "of people" (genitive) and a singular verb.