Which of the following sentences are grammatically correct in written text?
- You also are allowed to see your son.
- You are also allowed to see your son.
- Also, you are allowed to see your son.
- You are allowed to see your son also.
All are grammatically correct, but can have slightly different meanings.
You also are allowed to see your son.
This could mean that in addition to other things that you are allowed to do, you are allowed to see your son. Depending on context, it could mean that in addition to others being allowed, you are too. E.g. "Your son's wife is allowed to see him. You also are allowed to see him."
You are also allowed to see your son.
Pretty much the same as the previous. We would be less likely to use this form to say #2 above, i.e. that you are allowed along with others who are allowed. This would more likely mean #1, in addition to other things, you are also allowed, etc.
Also, you are allowed to see your son.
In addition to other things, you are allowed to see your son. This differs from the first two in that it can be used when the other things are not permissions, while the first two would generally be used only to discuss several different permissions. That is, for example:
You are allowed to have a lawyer present during questioning. You are also allowed to see your son.
Your deposit will be refunded. Also, you are now allowed to see your son.
You are allowed to see your son also.
This one is most different. It would normally be used if there are specifically others that you are allowed to see, and your son is one of those. Like, "You are allowed to see your daughter. You are allowed to see your son also." You wouldn't use this form with other permissions or with other things that are not permissions.
But note that if you put a comma between "son" and "also", then it becomes the same as "Also, you are ..."
You also are allowed to see your son and you are also allowed to see your son are correct, according to e.g. this site.
This English.SE answer says that also is often used with the verb.
I don't really know whether You are allowed to see your son also is correct, but it looks/sounds like it isn't.
And Also, you are allowed to see your son sounds/reads strange, but looks like it's correct.
The place that "also" takes in a sentence decides what the sentence would mean: to further explain, even if words in a sentence do not change, it is the particular place which "also" occupies in the sentence that the meaning of the sentence gets changed. Let me try to spell out a simple rule how the placing of "also" in a sentence changes its meaning: "also" when appears in a sentence qualifies the following word which denotes an object or action (or inaction) or, where there is no such following word, the preceding such word. This rule does not apply in the case where "also" appears in the beginning of a sentence followed by a comma or where "also" appears in the end of a sentence preceded by a comma. In this case, the entire sentence gets qualified by "also". This, I think, clears all doubts. However, as already explained above, none of the sentences which the question cites is grammatically incorrect.
"Also" comes after "to be." So number 1 and 3 is not correct. "Too" usually comes at the end of a clause so number 4 is not correct. Number 2 is the correct answer.
No. 2 is correct. As I have learned that "also" is only used after a verb and it cannot be used at the end of the sentence. We use too or as well in that case.
You are allowed to see your son also is incorrect, because also is never used at the end of a sentence. Instead it is required to use too at the end. It would be You are allowed to see your son, too. Other versions seem correct to me.