How to determine Multilanguage / Localisation Hierarchy

Localisation is an important and tough issue for everyone. While determining localisation keys, we should avoid duplication, determining text case (uppercase, lowercase, uppercase), articles, singular/plural and suffix/prefix correctly, creating clean hierarchy (according to controller, page, model or category).

Please, share your strategy and lead developers to handle this issue.

Solution

I am going to use this strategy. You can comment it to improve.

{ case } :: UC - Uppercase
{ case } :: LC - Lowercase
{ case } :: CC - Camelcase

For Specific Keys

{ category }. { page }. { key }.{ case }

examples

landing.city.title = { param0 } Cheapest Flights

landing.fromto.title = { param0 } - { param1 }  Cheapest Flights

Common or Basic Keys (Enums, Forms)

{ category }.{ key }.{ case }

examples

  landing.nearestAirports = Nearest Airports
  currency.TRY = TL
  gender.MALE = Male 
  searchForm.from = From
  searchForm.flexibleDates = Flexible Dates
  signinForm.username = Usernmame
  cabinType.ECONOMY = Economy
  passengerDetail.name = Name
  invoice.taxnumber =  Tax Number