 Most of the population () speaks German (82.9%), with Italian being second most common ( 3.6%) and Albanian being third ( 2.8%).The age distribution, , in Untersiggenthal is; 685 children or 10.7% of the population are between 0 and 9 years old and 766 teenagers or 11.9% are between 10 and 19.Of the adult population, 842 people or 13.1% of the population are between 20 and 29 years old.