Multilingual products

This page is to discuss how to handle products that have text in multiple languages on their label.

Problems addressed

Single products with more than one language on the label
- Bilingual products
  - Products where all the texts on the label are in two (or more) languages
  - Common in bilingual countries (Belgium, Canada...)
  - e.g. most Cora products have all the text in French and in Dutch: http://world.openfoodfacts.org/brand/cora
Products with some information in multiple languages
- e.g. ingredients and nutrition facts in many languages

Products that have different labels in different languages, with the same barcode
- will be addressed by Project:Product versions and history
Products that have different labels in different languages, with a different barcode
- we simply store them as different products
- we might consider linking the products in some way in a future project
Translating ingredients
- will be addressed by ingredients taxonomy

There is a field to indicate the "main" language of a product
- Values entered in the product edit form are considered to be in the "main" language of the product
- Values entered in fields for which we have a taxonomy (categories, countries, labels, traces) are mapped according to the "main" language of the product
  - e.g. entering "jus de fruits" in the categories field when the main language is set to French will result in en:fruit-juices to be assigned.
Values for nutrition facts are global and assigned to a canonical field
- Except when the nutrient's name is unknown (i.e. not in our current nutrient taxonomy)
Images are selected/cropped for the "main" language of the product (product front, ingredients and nutrition facts)

Fields for which we have a taxonomy (categories, countries, labels, traces) are displayed in the target language. (target language is set by the subdomain, e.g. using http://world.openfoodfacts.org , we will see categories in English even for French products, using http://es.openfoodfacts.org will result in Spanish)
- Only if the category exists in the taxonomy
- Only if the target language exists for this category in the taxonomy
  - If the target language doesn't exist, English is used to display the field value
Nutrition facts are displayed in the target language
Fields without a taxonomy are displayed in the language they were entered in
- common name, quantity, packaging, brands, origin of ingredients, manufacturing or processing places, city/state/country, stores, link to the product page, best before date
- ingredients
Images for product front, ingredients and nutrition facts are for the main language of the product (and not the target language)

Taxonomize as many fields as possible
- Taxonomized field need to be completed in only one language
- Packaging, origins of ingredients, purchase places
  - Note: packaging and purchase places do not correspond to text on the label
Enable users to enter data for more than one language:
- Select different images or different part of the images for product front, ingredients and nutrition facts
- Enter data (text) for more than one language

Taxonomized fields will be displayed in the target language
Display other fields and pictures in the target language if the product has data in that language
Indicate in which languages the product data is available, and provide a way to see it

How to make data entry not too overwhelming?
Solution 1: tabs to switch between languages
- + button to add a language tab
- tab displays only the fields that need to be completed in other languages:
  - images
  - fiels like generic name, ingredients
Solution 2: multiply each field by the number of languages, display all languages for one field together
- + button to dynamically add a new language

Packaging, origins of ingredients and purchase places are tag fields (they contain comma separated values) that are not yet taxonomized
The existing taxonomy system will take care of the mapping between different languages
The taxonomies need to be created or completed
To be determined: what to do with brands?
- Typically not translated
  - But exceptions exist
- Could benefit from being taxonomized in order to have a hierarchy

Keep all exisiting fields as-is
- e.g. ingredients, generic_name etc.
- "ingredients_text":"Chocolate, milk"
- For compatibility and to enable incremental implementation and deployment
Create new fields suffixed by _lang, with a hash
- "ingredients_text_lang":{"en":"Chocolate, milk", "fr":"Chocolat, lait"}
Create new languages field
- Hash that contains languages for which we have values for at least one field
- "languages":{"en":"1", "fr":"1"}