 Most of the population () speaks German (84.2%), with Serbo-Croatian being second most common ( 5.5%) and Turkish being third ( 5.0%).The age distribution, , in Unterkulm is; 270 children or 9.3% of the population are between 0 and 9 years old and 407 teenagers or 14.0% are between 10 and 19.Of the adult population, 365 people or 12.6% of the population are between 20 and 29 years old.