How do linguists distinguish a Tibeto-Burman language from a dialect?

Linguists face significant challenges in distinguishing between a language and a dialect within the Tibeto-Burman family. Because many of these languages remain under-studied or undocumented, the distinction is often elusive and, to some extent, arbitrary.1

Several factors complicate this classification:

• Nomenclature Confusion: There is a profusion of different names for the same linguistic variety. A single language may be known by multiple autonyms, exonyms, paleonyms, and neonyms, making it difficult to determine if two names refer to distinct languages or merely different designations for the same dialect.1
• Sociopolitical Influence: Political and ethnic factors frequently influence how a variety is labeled. In some cases, names are used inconsistently, referring to a specific language in one context and a broader group of related languages in another.1
• Lack of Data: Many Tibeto-Burman languages are known only through limited word lists or have not yet been described in sufficient detail to allow for valid comparative analysis.2
• Relative Intelligibility: While linguists often use mutual intelligibility as a criterion—where dialects are mutually intelligible and languages are not—this is a relative measure. In many regions, the lack of a standard language makes these boundaries difficult to define.3

Ultimately, the elusiveness of this distinction is a primary reason why it is impossible to determine the exact number of Tibeto-Burman languages.1