tu and toi in the same sentence

[Joakim Rosqvist]

I'm trying to augment my daily "duolingo" French lessons by reading  Le petit prince.

On p.16 I find this:

    - Alors, toi aussi tu viens du ciel !

confused about seeing both toi and tu, I fed it to google translate:

    Then you also come from the sky!

and back to French again:

    - Alors, tu viens aussi du ciel !

That last French sentence makes sense to me, but how does it differ in meaning from the original?

[George Hunt]

It feels to me as if "toi aussi" in in parentheses.

It serves to emphasise the "tu" which is the subject of the sentence.

It is a bit like a repetition of the subject (even though it comes first)

It is a very common expression so you should be prepared to come across it again.

"Lui aussi" ,"elle aussi" "nous aussi" etc can be used in the same way.

[Robert]

Google's "you also come from the sky" seems to imply other unmentioned possibilities : come from earth, from clouds, from water, etc.
But that's not the meaning of the French statement.

I propose these translations :
You too, you come from the sky.
You, also you, come from the sky.

(The implication is there are people or things like you, that also come ...)

[Lefevre]

It's exactly what George says, it only works as emphasing the "tu".
They talk about it here : http://www4.ncsu.edu/~dsbeckma/110Tutoiton.html
"They are used in a variety of situations in French, most often in short answers without verbs, for emphasis, or for contrast with subject pronouns".
A negative sentence, smth like "unlike you, he...", is translated "contrairement à toi, il..."