Simalungun languages are sometimes partially mutually intelligible with both Northern and Southern Batak, but more comprehensible with other Southern Batak languages (Toba-Angkola-Mandailing).
The Simalungun language is often partially graspable by speakers of both the Northern and Southern Batak dialects, but it is generally easier to comprehend for those who speak other Southern Batak languages such as Toba-Angkola-Mandailing.