The largest distinguishing aspect of the language spoken in Argentina and Spain is the large number of Italian and German settlers in Argentina that have influenced themlanguage and pronounciation. (i think I got that right)
That's right. And even lunfardo, our local slung, is based on these influence (with some loans from Portuguese).
But before the massive arrival of these European immigrants, Argentina had its own popular variant of Spanish, different from standart Spanish. This variety had developped without foreign influences, and was probably a product of the isalotion experienced by Spaniards in the territory of present day rural argentina.
This form of Spanish was spoken by gauchos in the fields (gauchos that represented up to 70 % of the population), and was dominant among this population at least tilll the 1870ies. Immigration and standart public education eventually changed this, and this native "dialect" gradually faded off.
I don't know if you could call it a dialect or not, but it was slighltly different from Standart Spanish.
Maybe if Argentina had kept been ruled by Conservative tyrans asRosas throughout the XIX century, hadn't recieved many immigrants, and hadn't developped a good education system, these "speech" would have been more widespread. Eventually, some hyper-national populist leader might decide its a different language and make it the "language" taught in schools
Here's an example of this speech, in Martín Fierro (of course, it doesn't look that different fron Spanish when written, you've got to hear it spoken)
[FONT=Arial,Helvetica,Geneva,Swiss,SunSans-Regular]Soy gaucho, y
entiendaló[/FONT]
[FONT=Arial,Helvetica,Geneva,Swiss,SunSans-Regular]Como mi lengua lo
esplica:[/FONT]
[FONT=Arial,Helvetica,Geneva,Swiss,SunSans-Regular]Para mí la tierra es chica[/FONT]
[FONT=Arial,Helvetica,Geneva,Swiss,SunSans-Regular]Y pudiera ser mayor;[/FONT]
[FONT=Arial,Helvetica,Geneva,Swiss,SunSans-Regular]Ni la víbora me pica[/FONT]
[FONT=Arial,Helvetica,Geneva,Swiss,SunSans-Regular]Ni quema mi frente el sol.[/FONT]
[FONT=Arial,Helvetica,Geneva,Swiss,SunSans-Regular]Nací como nace el
peje[/FONT]
[FONT=Arial,Helvetica,Geneva,Swiss,SunSans-Regular]En el fondo de
la mar;[/FONT]
[FONT=Arial,Helvetica,Geneva,Swiss,SunSans-Regular]
Naides me puede quitar[/FONT]
[FONT=Arial,Helvetica,Geneva,Swiss,SunSans-Regular]Aquello que Dios me dio[/FONT]
[FONT=Arial,Helvetica,Geneva,Swiss,SunSans-Regular]Lo que al mundo
truje yo[/FONT]
[FONT=Arial,Helvetica,Geneva,Swiss,SunSans-Regular]Del mundo lo he de llevar[/FONT]