UX Issues in doing Partial localization

Question

I did see this question Translation strategy for only part of a site and though the points raised in that are helpful, they are not applicable in my context.

I am designing a site where there was a request to localize just one section of the page to reflect the language of the person coming in. For example, if the person coming in spoke English the section would say"

Welcome Mr John Doe, Thank you for visiting ... and we hope you enjoy your time here

However if he was Spanish it was required to say

Bienvenido Sr. John Doe, Gracias por su visita ... y esperamos que disfrute de   su tiempo aquí

My primary concern is two things :

1. Wont it be a jarring experience to have a different language in just one module (the rest of the content is in English and will not be changed)
2. If my welcome text is going to in Arabic or any right to left language and only in that module, do I have to flip the design layout for that module only or for the entire module (while designing for RTL languages we should not only modify the language but also the design layout to follow the normal reading path) ?

Answer 1

I would suggest not to do it. After seeing the website in my native language, I will expect it to be the same through out. After navigating to the next page and see that the posts are in different language, I will spend at least few minutes trying to figure out how to change it back. Basically this way I will spend time trying to understand why the language changed... This will cause frustration and not very positive UX.