The following is the hierarchy of precedence for different Language.properties files to override each other:
Language-ext.properties takes precedence over Language.properties.
Language specific versions take precedence over the non language specific versions. For example, Language_en.properties takes precedence over Language.properties.
Location specific versions take precedence over the non location specific versions. For example, Language_en_US.properties takes precedence over Language_en.properties.
For the Language.properties file for English, the following is the hierarchy of precedence, where Language-ext_en_US.properties will have the highest precedence and the Language.properties file will have the least precedence:
Language-ext_en_US.properties
Language_en_US.properties
Language-ext_en.properties
Language_en.properties
Language-ext.properties
Language.properties