And the second data analysis comparative analysis was used in this study to analyze the data and it is written in a descriptive style. The results of this research consist of two sections: the first section is the analysis of factors influencing the ineffectiveness of English translated version on signboards categorizing into three main factors: the use of word, the use of English grammar and the inappropriate translation, the second section is the explanation of opinions from Thai people and foreigners towards the use of English on the public relations signboards as a reflection of the effectiveness of English translated version on signboards.