The tree metaphor represents speech production as open-ended generation: an utterance is not globally completed before speech begins, but launches when a local structure crosses a threshold under the constraint of an overarching intention, and then develops through incrementality and recursion.

Macroplanning: the branch network

Through macroplanning, the overarching intention diffuses into a Subgoal Network. Linearization establishes relations and an order of advance among subgoals, forming the macroscopic trunk-and-branch organization of discourse growth. When processing enters the current subgoal, functional orientation specifies the local direction of growth, conceptual focus becomes the organizing center, and relevant conceptual nodes form a Local Conceptual Network.

Microplanning: the local bud

The local conceptual network is analogous to a bud at a node. Although not yet extended into a branch, a bud already possesses a growth center, an internal configuration, an initial axis, and a connection to the parent branch. Correspondingly, a microplan is not yet a complete utterance, but it has organized the conceptual elements required around the current focus, established a minimal relational configuration, and retained a functional connection to the current subgoal and the discourse already produced.

Threshold: the onset of growth

The threshold marks the critical transition from potential organization to linguistic realization. When the minimal relational configuration centered on the conceptual focus acquires the capacity for linguistic encoding, the bud begins to sprout and the local structure enters formulation. The threshold is therefore not the completion of planning, but the moment at which a local network with a minimally sufficient generative configuration acquires the capacity for actual growth.

Incrementality and recursion

Formulation initiates the extension of the branch. Incrementality incorporates new conceptual nodes into the current local network; recursion allows a newly incorporated node to become a new organizing center and trigger another local network. Each newly formed structure is both the outcome of current processing and a condition for subsequent processing.

Macroplanning and microplanning thus instantiate the same network-generating logic at different scales. Macroplanning generates and develops the subgoal network; microplanning generates and develops the local conceptual network. Both sustain speech through node formation, threshold crossing, incremental expansion, and recursive reorganization.

Macroplanning generates the branch network; microplanning forms the local bud; the threshold initiates sprouting; incrementality drives extension; recursion produces new buds.