Linguistic validation refers to the processes and techniques that are used to ensure that the translation of a given text is linguistically accurate, takes into account cultural differences that may impact its meaning and is validated by a professional in the field which the text applies to.
It is most often used in clinical trials and other healthcare research where the meaning and context of the words used in a text can have significant impact on the validity of the research or trial being conducted.
A linguistic validation service provides a set of processes that are used to ensure that a translation is linguistically accurate. This process usually involves translating the text, having it assessed by experts in the language and then translating the text back into the original language and assessing whether any meaning has been lost in the process. This requires considerable expertise and resources which is why many companies outsource the function to translation services.