S, A and P
For a canonical intransitive clause, typologists label the sole core argument S. In a canonical two-argument transitive clause, A is the more agent-like argument and P the more patient-like one. These are comparison positions, not claims that every predicate has a simple actor or that each language has the same grammatical notion of “subject.” Alignment asks which of S, A and P are coded alike in a particular grammatical domain.
In nominative–accusative case marking, S and A share coding while P differs. In ergative–absolutive marking, S and P share coding while A differs. Neutral, tripartite and active–inactive patterns are also documented. WALS chapter 98 compares case marking of full noun phrases; it treats pronouns separately because their pattern may differ. Alignment of verbal person marking is another question again. A language-level label should always state which domain is meant.
A coded comparison
WALS illustrates nominative–accusative case marking with modern Latvian: a noun ending appears on the sole argument of “fly” and on the actor of “draw,” while the object of “draw” takes a different case. The instructive point is the comparison across an intransitive and a transitive construction. Without both, a single case form cannot establish alignment. In English, full nouns show no case contrast of this kind while some pronouns distinguish forms like we and us; coding only nouns or only pronouns gives different results.
Differential marking requires further care. WALS discusses modern Spanish a with certain specific animate objects but not with ordinary inanimate objects. If a marker is absent in one clause, that does not by itself make the whole system neutral. Check animacy, definiteness, person, tense and construction before assigning a value.
Predication is broader than verbs
A related typological question asks how a language says “X is Y.” WALS chapter 120 compares overt and zero coding of stative nominal predicates. “Zero copula” is a descriptive label for an overt-linking element absent in a construction, not an allegation that the language has a missing word or defective grammar. A language may also distinguish nominal, adjectival and locational predicates. To code an ancient language, gather actual predication types and periods rather than translating every clause with English is.
Exercise: identify S, A and P in one intransitive and one transitive sentence from the same variety. Write separate columns for noun case, adpositions and verbal agreement. If one column lacks a contrast, do not infer that the others do too.
Modern-language examples on this page clarify a linguistic pattern. They do not establish unattested sounds or forms for an ancient language. Follow the cited sources below and keep editorial readings separate from the surviving trace.