I actually was wondering this same thing recently. My thought was that maybe
the infinitive could be replaced by the gerund. So "I like to run" becomes
"I like running" and "I am permitted to run" would be "I am permitted
running". Maybe that'd work?

... ..... ....... ... ..... ....... ... ..... .......
Michael D. Martin, Master Mason
S. W. Hackett Lodge #574
F&AM of California

-----Original Message-----
From: Constructed Languages List [mailto:[log in to unmask]] On
Behalf Of Gary Shannon
Sent: Thursday, November 25, 2010 11:10 AM
To: [log in to unmask]
Subject: Missing infinitive

Is the infinitive something a language MUST have?

So far, Txtana (my 30-day conlang) has no infinitive form of the verb.
And so far, I don't feel any need to introduce one. But in sentences
like "I like to run." (Raxo havato setu.) the sentence just didn't
feel right to me. So I modified the way those constructions are
handled, still not using an infinitive form. Instead of using two
verbs in "I like to run." Txtana now uses a passive participle form of
the first verb as if it were an adverb. So the verb "to like" (or
similar verbs like: to be able to, to be allowed to, to intend to, to
prefer to,... etc.) becomes:

raxo = like (remember 'X' is pronounced "sh")
passive = na + raxo = naraxo. (to be liked)
participle = ~e instead of ~o = naraxe. (liked-ADV/ADJ)
havato = run

Naraxe havato setu.
Is-liked run PRES-me.
I like to run. (I like running.)

liso = to permit, to allow
naliso = to be permitted, to be allowed
nalise permitted (ADJ/ADV)
Nalise havato setu.
Is-permitted run PRES-me.
I am allowed to run.
I may run.

This seems to work fine with no infinitive. Are there natlangs other
than strictly analytical ones that lack the infinitive?