Not all translation adapters are made equal. Some have more features than others, and some perform better than others. Additionally, you may have business requirements that force you to use a particular adapter. However, if you have a choice, which adapters are fastest?
Zend Framework ships with a variety of translation adapters. Fully half of them utilize an XML format, incurring memory and performance overhead. Fortunately, there are several adapters that utilize other formats that can be parsed much more quickly. In order of speed, from fastest to slowest, they are:
Array: this is the fastest, as it is, by definition, parsed into a native PHP format immediately on inclusion.
fgetcsv()to parse a CSV file and transform it into a native PHP format.
parse_ini_file()to parse an INI file and transform it into a native PHP format. This and the CSV adapter are roughly equivalent performance-wise.
Gettext: The gettext adapter from Zend Framework does not use the gettext extension as it is not thread safe and does not allow specifying more than one locale per server. As a result, it is slower than using the gettext extension directly, but, because the gettext format is binary, it's faster to parse than XML.
If high performance is one of your concerns, we suggest utilizing one of the above adapters.