Imperative-and-Declarative (IaD) is a very peculiar construction where an imperative is used in conjunction with a declarative clause, but this does not imply any order or even permission. This construction is illustrated by a sentence like ‘Go on like this and you will fail’. In this example, the imperative does not convey any order or suggestion but, rather, is very similar to a conditional clause (‘If you go on like this, you will fail.’). Since this use of the imperative is systematic across languages, the Imperative-and-Declarative construction has even been claimed to be a proper test for imperatives. LIS has the Imperative-and-Declarative construction, as shown in the example below which contains the imperative sign palm_up.
hn
laugh palm_up ix1 fail
‘Keep laughing and I’ll fail you!’
The sentence-initial clause of the sentence above is marked by specific non-manual marking roughly composed of repeated head nodding (hn), raised brows (re), and optionally tensed eyes (‘te’). The non-manuals marking in this sentence, together with the sign palm_up, are responsible for the peculiar interpretation of the sentence, which is minimally different in meaning from the conditional sentence below, which, however, lacks the sign palm_up and is marked by the typical non-manuals of conditional clauses in LIS (SYNTAX 3.5.1).
hn
re
laugh ix1 fail
‘If you laugh, I’ll fail you.’