Reciprocal constructions express two simple situations or actions occurring in opposite directions. In some languages, reciprocity is expressed iconically: two simple clauses are juxtaposed or coordinated; the main verb is repeated, and the roles are reversed from one to the other. Most languages have reciprocity markers (e.g., verbal affixes, pronouns, particles, adverbials) that allow the predicate to only appear once. Some reciprocity markers mark only reciprocity, while others may express a second meaning, such as reflexivity or collectivity.
Non-iconic strategies for encoding reciprocity may be restricted to a particular set of verbs: for example, transitive verbs that feature a real agent and real patient in semantic terms; a very limited set of specific verbs; verb forms that allow only one additional (non-singular) NP as agent or patient. For verbs not included in this limited class, reciprocity may be expressed iconically. If a language thus displays more than one strategy, the parameter values should be listed with an ampersand (&).
RcprIcon: Reciprocity can only be expressed iconically: the two sentences appear alongside each other in inverse structures (the agent of one sentence appears as the patient of the other, and vice versa), with repetition of the verb.
RcprNonRefl: Reciprocity is expressed with a single verb; the grammatical encoding of reciprocity is different than that of reflexivity.
RcprReflNonRefl: Reciprocity is expressed with a single verb; the grammatical encoding of reciprocity has some overlap with that of reflexivity.
RcprRefl: Reciprocity is expressed with a single verb; the grammatical encoding of reciprocity is the same as that of reflexivity.
 For example: “I love her and she loves me.”
 For example, the language allows the structure The children love each other, but not Hansel and Gretel love each other.
 For languages that display multiple parameters, it is particularly important to include description of these strategies and their use in the commentary.
 This does not necessarily entail ambiguity, since the meaning of the verb, along with other grammatical or pragmatic considerations, may clarify the intended meaning. Consider, for example, the French il s’aime; the verb is unambiguously reflexive (‘he loves himself’), while ils s’aiment, despite its structure, is almost certainly reciprocal (‘they love each other’), since its use as a reflexive construction would generally be accompanied by reinforcing strategies, such as sois-mêmes, to clarify that its meaning is reflexive.