An impersonal construction consists of the third person singular of the verb, in any relevant tense and aspect, with the third-person epicene singular pronoun lea as its subject. Some verbs only exist in these constructions: lea crysat "it snows"), some have a different meaning than the plain verb would suggest: chyla "to become visible", lea chylat "it seems".
The impersonal construction is inseparable; the only thing that can squeeze between lea and the verb is the verbal negation na. Even the question particle a comes before lea.
Lea doesn't unconditionally occupy the subject position, but either pulls the verb forward out of its usual sentence-final position or goes with it to the end of the sentence.
When a sentence has no real (explicit or implicit) subject, lea can be used as a dummy subject:
lea daysenat 3sE rain-PRS-3s
lea verynat 3sE dawn-PRS-3s
"The dawn breaks"
The construction can have an object, which is either a verb in the infinitive or an object phrase:
trisa lea naperat steal-INF 3sE NEG.permit-PRS-3s
"Stealing is forbidden" (generally)
lea naperat naruma 3sE NEG.permit-PRS-3s NEG.work-INF
"No loafing" (specifically in this situation)
daysena lea chylat rain-INF 3sE appear-PRS-3s
"It seems to rain", "It looks like it's raining"
lyase jom no nabochet lea chylat woman that whether NEG.rich-IRR-3s 3sE appear-PRS-3s
"That woman seems to be poor"
Riei so Rava bornea trisayt lea dilynut Riei-nom and Rava-nom horse-acc-s steal-PRS-3p 3sE happen-PRT-3s
"It happened that Riei and Rava stole a horse", "Riei and Rava happened to steal a horse"
In the last example only the impersonal construction has a marked tense; trisayt "they steal" is put in its time by lea dilynut "it happened", that is, it's understood to have occurred simultaneously.
If the verb in the object phrase has a subject a finite verb is required; there's no accusativus cum infinitivo in Ilaini. The object phrase occupies the normal object position. If there's any doubt about the verb in the object phrase, the irrealis is used, with optional no "whether".
Ilaini has no real passive voice. What would be the subject of the passive takes the accusative case and is treated as the grammatical direct object of an impersonal construction:
lea trisenat vensinan 3sE steal-PRF-PRS-3s silver.piece-acc-c
"Money has been stolen"
vensinan lea trisenat silver.piece-acc-c 3sE steal-PRF-PRS-3s
"The money has been stolen"
The verbal negation na, and nothing else, can come between lea and the verb:
vensinan lea na trisenat silver.piece-acc-c 3sE NEG steal-PRF-PRS-3s
"The money has not been stolen"
With an indirect object:
valen lea trisenat vensinan king-dat-s 3sE steal-PRF-PRS-3s silver.piece-acc-c
"Money has been stolen from the king"
ni valen vensinan lea na trisenat NEG king-dat-s silver.piece-acc-c 3sE NEG steal-PRF-PRS-3s
"The money has not been stolen from the king", "It is not from the king that the money has been stolen"
And in a relative clause:
vensin li valen lea trisenat silver.piece-nom-c REL king-dat-s 3sE steal-PRF-PRS-3s
"The money that has been stolen from the king"
salea valen vensinan trisenat someone king-dat-s silver.piece-acc-c steal-PRF-PRS-3s
"Someone has stolen money from the king"
At an earlier stage of the language lea could be used as the subject of a "normal" verb to refer to a person of unspecified gender or an unspecified person ("one"). Nowadays, lea as a common-gender personal pronoun is strictly an object form.
These usually express a situation that the subject has no control over.
lea mudhat Alysea 3sE heal-PRS-3s Alyse-acc
"Alyse gets better", "Alyse is healed"
Alysea lea chalat mudhea Alyse-acc 3sE see-PRS-3s health-acc-s
"Alyse looks healthy"
Another example of this is lea chylat "to seem".
calesh lea namudhat calesh 3sE NEG.heal-PRS-3s
"Calesh makes (one) ill"
As calesh is an indeclinable word this is ambiguous: either calesh is the object of the impersonal expression lea namudhat, or calesh is the subject of namudhat and lea is its object. Let's try with something that we can decline:
alab lea namudhat brandy 3sE NEG.heal-PRS-3s
"Brandy makes (one) ill"
Alab is in the nominative (the accusative would be alba): it must be the subject. Infinitives can also appear in this position:
brusa lea namudhat smoke-INF 3sE NEG.heal-PRS-3s
"Smoking makes (one) ill"
A common application of this variant of the impersonal construction is naming people:
lea furat Ayrean 3sE name-PRS-3s Ayran-acc
"He is called Ayran" (neutral)
Ayrean lea furat Ayran-acc 3sE name-PRS-3s
"Ayran is his name" (emphasis on the name)
a lea furat Ayrean? Q 3sE name-PRS-3s Ayran-acc
"Is he called Ayran?"
ti lea furat Ayrean 2s-O 3sE name-PRS-3s Ayran-acc
"You are called Ayran" (neutral)
lei lea furat Ayrean 3sM 3sE name-PRS-3s Ayran-acc
"He is called Ayran" (emphatic)
ti a lea furat Ayrean? 2s-O Q 3sE name-PRS-3s Ayran-acc
"Is your name Ayran?" (neutral)
ti Ayrean a lea furat? 2s-O Ayran-acc Q 3sE name-PRS-3s
"Is your name Ayran?" (surprised)
Ayrean furat Ayran-acc name-PRS-3s
"He/she calls Ayran" (by name)
salea Ayrean furat someone Ayran-acc name-PRS-3s
"Someone calls Ayran"
salea Ayrean lea furat someone Ayran-acc 3sA name-PRS-3s
"Someone is called Ayran", "There is someone called Ayran"
razie lea Ayrean furat youth-nom-s REL Ayran-acc name-PRS-3s
"The young person who calls Ayran"
razie lea Ayrean lea furat youth-nom-s REL Ayran-acc 3sE name-PRS-3s
"The young man who is called Ayran"
When a pronoun follows an identical pronoun, only one is realised:
salea lea furat Ayrean someone REL/3sE name-PRS-3s Ayran-acc
"Someone who is called Ayran"
Here lea serves both as relative pronoun and as the subject of the impersonal construction.