Use i18n-http-backend to load translatiosn from json files.

public/locales/en/invoice-row.json

@@ -0,0 +1,7 @@
+{
+  "enter_item": "Enter item",
+  "enter_quantity": "Enter quantity",
+  "enter_unit": "Enter unit",
+  "enter_price": "Enter price",
+  "enter_tax": "Enter tax"
+}