This is a sample skill that shows how to internationalize it - the easy eay.

Install python-i18n

$ pip install python-i18

$ pip install -r requirements.txt -t .

Create a folder where all files with the translated strings will be places

$ mkdir translations

Create the correspondent JSON files for each language to be supported. For example:

$ touch es-ES.json
$ touch en-US.json

Using as an example the Hello World Skill:

en-US.json

{
    "WELCOME_MESSAGE": "Welcome, you can say Hello or Help. Which would you like to try?",
    "HELLO_MSG": "Hello Python World from Classes!",
    "HELP_MSG": "You can say hello to me! How can I help?",
    "GOODBYE_MSG": "Goodbye!",
    "REFLECTOR_MSG": "You just triggered %{intent}",
    "ERROR": "Sorry, I had trouble doing what you asked. Please try again."
}

es-ES.json

{
    "WELCOME_MESSAGE": "Te damos la bienvenida, puedes decir Hola o Ayuda, ¿qué deseas hacer?",
    "HELLO_MSG": "Hola!",
    "HELP_MSG": "Puede saludarme, ¿en que te puedo ayudar?",
    "GOODBYE_MSG": "Hasta Luego!",
    "REFLECTOR_MSG": "Acabas de iniciar ${intent}",
    "ERROR": "Perdona, no te he entendido, inténtalo de nuevo por favor."
}

Import the package i18n

import i18n

Add the configuration needed to make i18n work as we need:

1. i18n.load_path.append('./translations')
2. i18n.set('skip_locale_root_data', True)
3. i18n.set('file_format', 'json')
4. i18n.set('filename_format', '{locale}.{format}')

Line 1: Tells the package where to look for the translations.
Line 2: Configures i18n to skip the root of the JSON file.
Line 3: Configures i18n to use JSON instead of the default YAML.
Line 4: Tells i18n what is the format of the filename. In this case it can be es.json or es-ES.json.

Add a request interceptor to get the locale of the request every time. Using the AbstractRequestInterceptor class.

1. class LocalizationInterceptor(AbstractRequestInterceptor):
2.     def process(self, handler_input):
3.         locale = handler_input.request_envelope.request.locale
4.        i18n.set('locale', locale)

Line 1: Get the locale from the request everytime.
Line 2: Configures i18n to use that locale which matches the name of each supported translated language.

Using the translated strings is as follows:

speak_output = i18n.t(‘<etiqueta>’)

i.e: speak_output = i18n.t('WELCOME_MESSAGE')

When using placeholders:

speak_output = i18n.t(‘<etiqueta>’, <placeholder_name>=‘<value>’)

i.e: intent_name = ask_utils.get_intent_name(handler_input)
      speak_output = i18n.t('REFLECTOR_MSG', intent=intent_name)

frivas / i18n-sample-skill