In advanced functional linguistics and sociolinguistics, spoken language serves multiple macrosocial and interpersonal roles, classified under distinct communicative functions such as transactional, interactional, phatic, and metalinguistic. Consider the following four advanced propositions regarding the functions of language in listening and speaking: I. Transactional language functions primarily to establish and maintain social relationships, camaraderie, and solidarity among interlocutors (e.g., casual small talk at a social gathering), where the precise exchange of factual information is secondary to affective bonding. II. Interactional language functions primarily to convey information, achieve explicit communicative goals, and ensure the successful delivery of goods, services, or facts (e.g., a customer service phone call or a pilot reporting flight telemetry to air traffic control), where message accuracy is paramount. III. Phatic communion refers to utterances that serve no informational or transactional purpose other than to signal sociability, break awkward silence, or maintain a social channel of communication (e.g., commenting on the weather during a chance elevator encounter). IV. The metalinguistic function of language—as defined within Roman Jakobson's model of communication—focuses on the linguistic code itself, allowing speakers to use language to discuss, clarify, analyze, or define features of the language code (e.g., asking, 'What does this lexical item mean in a formal register?'). Identify the option that correctly evaluates the linguistic, pragmatic, and theoretical validity of propositions I, II, III, and IV according to modern language pedagogy and Functions of language principles.

To determine the correct evaluation of the four propositions regarding the functions of language in listening and speaking, let us analyze each statement against established sociolinguistic and pedagogical frameworks (such as those by George Yule and Roman Jakobson): - **Proposition I is INVALID:** The description provided in Proposition I actually defines the *interactional* function of language, whereas the *transactional* function is concerned with message-oriented information exchange. Transactional language focuses on obtaining goods, services, or specific facts. - **Proposition II is INVALID:** The description provided in Proposition II defines the *transactional* function of language, not the interactional function. Interactional language focuses primarily on social maintenance, interpersonal relationships, and affective bonding. - **Proposition III is VALID:** Phatic communion (a term coined by anthropologist Bronisław Malinowski) describes utterances designed solely to establish an atmosphere of sociability or maintain social contact rather than to impart significant information (e.g., 'Nice weather we're having!'). - **Proposition IV is VALID:** According to Roman Jakobson's model of language functions, the metalinguistic function operates when the focus of the communication is on the code itself—using language to talk about language (e.g., defining words, clarifying grammar rules, or checking mutual understanding). Therefore, propositions I and II invert the core definitions of transactional and interactional talk, making them incorrect, while propositions III and IV accurately define phatic communion and the metalinguistic function. For a deeper understanding of these concepts, refer to Functions of language.