Shallow nesting

Claim: a sentence puts at most one clause inside another; with two nested clauses, readers already misread.

• Grade: measured in English, where readers misread at two nested clauses; not found in German, so the limit of one is a convention there.
• Evidence: psycholinguistics (strand 3), against.
• Check: clause-nesting (syntax, weekly): no sentence puts a clause in the middle of a clause that is itself in the middle of another; a clause at the end does not count.
• Reader styles: strengthened by novice; relaxed by LLM reader.

What it asks

• One embedded clause at a time; a second becomes its own sentence.
• Prefer a clause at the end of a sentence to one in its middle.

Why

With two nested relative clauses, English readers rate a sentence missing its middle verb as acceptable as the complete one (Gibson & Thomas 1999). Difficulty comes from finite memory, not from grammar (Miller & Chomsky 1963). In seven European languages, written text never nests past three clauses, and speech hardly nests at all (Karlsson 2007).

Legal text agrees, in experiments with excerpts written by a lawyer and lay readers recruited online. Legalese, which bundles centre-embedding with passives, rare words and capitals, lowered recall (35% against 42% for plain versions) and comprehension (Martinez 2022, measured). It did so even for readers with much reading experience. That centre-embedding weighed most comes from an exploratory analysis the authors call underpowered.

Limits

The limit depends on the language: German readers are not fooled the way English readers are (Vasishth et al. 2010). The corpus maximum counts what writers produced, not what readers can parse.