Add info for help w/ translations fixes #2806

README.md

@@ -5,6 +5,9 @@
 ## For Mirador Users
 You can quickly use and configure Mirador by remixing the [mirador-start](https://mirador-start.glitch.me/) Glitch.
 
+## Adding translations to Mirador
+For help with adding a translation, see [src/locales/README.md](src/locales/README.md)
+
 ## Running Mirador locally
 
 Mirador local development requires [nodejs](https://nodejs.org/en/download/) to be installed.

src/locales/README.md

+# Contributing a Mirador translation
+
+Mirador is built with internationalization and translation support. It uses a translation file and [react-i18next](https://react.i18next.com/) to provide translations in user interface elements.
+
+## Getting started
+To contribute a new language to Mirador, you will need to convert the strings contained in [en/translation.json](en/translation.json) to the target language.
+
+So we would want to create a directory for the target language using the iso language code that copies from the `en/translation.json` file. e.g. `fr/translation.json`.
+
+```sh
+$ mkdir src/locales/fr && cp src/locales/en/translation.json src/locales/fr/translation.json
+```
+
+For example, this subset of the English file:
+
+```javascript
+// src/locales/en/translation.json
+{
+  "translation": {
+    "aboutThisItem": "About this item",
+    "addedFromUrl": "(Added from URL)",
+    "addManifestUrl": "Resource location",
+    "addManifestUrlHelp": "The URL of a IIIF resource",
+    "addResource": "Add resource",
+    "annotationCanvasLabel_1/1": "Item: [{{label}}]",
+...
+```
+
+Would look like this in French.
+
+```javascript
+// src/locales/fr/translation.json
+{
+  "translation": {
+    "aboutThisItem": "A propos de cet item",
+    "addedFromUrl": "(Ajouté depuis une URL)",
+    "addManifestUrl": "Emplacement de la ressource",
+    "addManifestUrlHelp": "L'URL de la ressource IIIF",
+    "addResource": "Ajouter une ressource",
+    "annotationCanvasLabel_1/1": "Item: [{{label}}]",
+...
+```
+
+Strings contained in double curly braces `{{}}` should not be changed.
+
+The [`i18n.js`](../i18n.js) file should also be updated for the new language.