"Tá teideal nua ag an leabhar."

Translation: The book has a new title.

[anfeardathuil]

If you're reading this, you are not going insane: In a previous example, we established "ar an leabhar" was correct. This proves both are acceptable.

[GordMcFee]

My sentiments exactly.

[ginagillen]

agus mise

[Berkhead]

There is a new title on the book should be accepted. This is how I would say it in my West Virginia dialect.