Be concrete and specific: how speakers introduce novel topics in naturalistic language

We asked whether the concreteness and specificity of the language used by conversation participants change depending upon the familiarity and the presence/absence of an object discussed. Additionally, we explored whether interlocutors engaged in distinct abstraction processes (analogical comparison; superordinate categorization) and whether they focused more on object's features or on their own experience. We used the ECOLANG corpus (Gu et al., 2025), a semi-naturalistic dataset of interactions in which 31 knowledgeable "speakers" describe novel/known objects to an "addressee" when the object is physically present or absent. We analyzed 22,581 sentences produced by the "speaker" and measured the concreteness and specificity of 1,612 nouns used. Results showed that more concrete and specific nouns were used for novel objects suggesting a need for precise information. Additionally, abstraction processes were more likely when the object was present and novel. Finally, when the object was present and known, interlocutors focused more on personal experience.