Debitive modality of a proposition p says that p is required. It comprises some more specific modalities:

• Necessitative modality of p says that p is necessary. It may be coded by expressions such as ‘p must be’, ‘p is needed’.
• Obligative modality of p says that some N is obliged to p. It may be coded by expressions such as ‘N must/ought to p’.
• Suitability of p says that p is or would be suitable. It may be coded by expressions such as ‘p is/would be appropriate/advisable’, ‘p should be the case’.

The difference between necessitative and obligative modality consists in the former being impersonal while the latter involves some N who is subject to the debitive modality. English must and Spanish deber do not distinguish these two modalities. Cabecar codes necessitative modality by kianá̱ p ‘p is needed’, but obligative modality by N ká̱wä́ta p ‘N is obliged to p’.

The difference between suitability and the other modalities consists in its deriving from possibly ad hoc moral or pragmatic considerations, thus being less dogmatic. Spanish distinguishes suitable conviene que p from necessitative or obligative p debe (realizarse).