I would guess that Peano used the ablative because it allows for plurals in -s without any problems. Sure it's interesting for a language if you have some of those second and third declension nominative forms - vox, ager, pater, nomen - but they don't play along with the plural in -s or even in -es. Do you really want "paters" or "pateres", "nomens" or "nomenes" when you can just have "patres" and "nomines"? What exactly does "vox" become - voxes or voces? It's worse with -us words - "muruses"? You get "muros" with the ablative. It just makes more sense, and since every LsF noun ends in a vowel, you wind up with an extremely regular plural.

On Fri, Feb 14, 2014 at 9:48 AM, Kjell Rehnström <[log in to unmask]> wrote:
Hi you all!
When reading a shorter text in Interlingua it suddenly struck me that both LsF and Interlingua IALA use the words taken from Latin in the ablative case. And yes, I know that this is not the whole truth, at least not for Interlingua, and I know as well that for Latino sine Flexione Peano really selected the ablative case of Classical Latin. At the same time the choice of a simplified Latin had as a reason that there already do exist dictionaries to most vernaculars. Buth then, why not take a shorcut and use the nominative of the Latin words.

Gabriel Svoboda showed what that would look like in the group Saluto on Facebook. It goes like this:
Latinum sine flexio:

Haitia celebra dies anniversarium ducentesimum decimum de suum libertas ab Francia, quem illo declara in dies 1º de mensis Januarius de annus 1804. Haitia es civitas Caribaeum, que maximum commercia cum Plus Civitas Foederatum de America. Plus Dominicanus (de Republica) es plus optimum amicus de plus Haitiensis in Facebook. In Consociatio de Plus Natio, Haitia saepe seque sententia de Sanctum Lucia et Mexicum.

Bruneium celebra dies anniversarium trigesimum de suum libertas ab Britannia. In dies 1º de mensis Januarius de annus 1984, proclamatio de libertas es lectum ab Hassanal Bolkiah, Suum Majestas Sultanus et Summum Dominus de Bruneium, Mansio de Pax. In Consociatio de Plus Natio, Bruneium saepe seque sententia de Malaysia et Brasilia. Plus Malaysianus es plus optimum amicus de plus Bruneiensis in Facebook. Bruneium maximum commercia cum Japonia."

Kjell R