Spanish: "Le" or "Les" in this sentence?

Yes you're right but there's no use telling the majority of native speakers that they're "wrong". I happened to have my grammar reference out and here's what it says:

There is a strong tendency in spontaneous language everywhere to use the singular le in this construction for the plural les, especially, but not exclusively, when the pronoun refers to a human being. Le for les is quite widespread even in formal speech.

Cualquiera le da vuelta a las razones por las que te viniste conmigo (Spain, dialogue)

...no darle importancia a los detalles.

¿Quieres devolverle la isla de Manhattan a los Algonquins? (Carlos Fuentes, Méx.)

Le viene natural a los niños (educated Spaniard, but not universally accepted in Spain)

Bayardo San Román le puso término a tantas conjeturas (Gabriel Garcia Marquez, Col.)

Sentences like Él les da mucha importancia a las apariencias" sounds odd to a lot of native speakers. They prefer le even though it's technically wrong. What happens in real life is that people speak this way, but when writing they proofread and stick in -les- or they remove the pronoun altogether, if possible.

Hope this helps a bit. Good luck!

I'd say in this case it means PORQUE or due to the fact that. Different examples i will feel of: No cuelgues el teléfono que te estoy hablando. Haz tus deberes que te estoy mirando. Corran que nos está siguiendo un perro rabioso. Sigan bailando que la música no terminó. Entra a casa que hace mucho frío afuera. And so on.

Mmm!!!... I must say I have to desagree whith Xenia this time, she is a great answerer in matter of Spanish language by the way, the correct way is:

"La niña LES tiene miedo a las serpientes"

That's because you use "Le" or "Les" deppending on the object ("serpientes" in this case) not the subjet (niña). What actually depends on the number of the subjet (wheter it is singular or plural) is the number of the verb ("tener" in this case)…, and the article of the object ( first “la”) of course.

Here you have an example of the 4 possible combination of singular and plural, I used capital letters in purpose to help you understand how it works:

La niña le tiene miedo a la serpiente. (everything in singular)

La niña leS tiene miedo a laS serpienteS ("ñina" in singular so first “la” and "tiene" in singular / "serpientes" in plural so "les" and second "las" in plural)

LaS niñaS le tieneN miedo a la serpiente ("niñas" in plural so first "las" and "tienen" in plural / "serpiente" in singular so "le" and second “la” in singular)

laS niñaS leS tieneN miedo a laS serpienteS. ( "niñas" and "serpientes" in plural so everything but "miedo" in plural)

I hope it helped you, you can find more examples in my video:

http://youtu.be/dWbZ1Wl1CV0

The correct word is "LES", because "arañas" is plural. But the 90% of people who speak Spanish natively would say "LE", I don't know why.

I speak it natively and I always say it incorrectly.

LE is correct because the word nina is singular

Plural i.e ninas would be les

Hope this helps

STUDIED AND LIVED IN FRANCE