The character 咱们 is formed by combining two components: 咱, which itself is a fused colloquial unit historically derived from 自 (self) and 口 (mouth), suggesting a spoken self-reference, and 们, a common suffix denoting plurality. The fusion creates a single lexical unit where 咱 establishes the first-person base, and 们 expands it to a collective, but the unique formation of 咱 imbues the entire word with an inherent, inseparable sense of inclusion, making 咱们 a dedicated, single-term expression for "we" that explicitly includes the listener, born from merging the concept of "self" with "mouth/speech" and then pluralizing it.