diff --git a/lingua_franca/format.py b/lingua_franca/format.py
index 4e93a300..51c3e99a 100755
--- a/lingua_franca/format.py
+++ b/lingua_franca/format.py
@@ -18,19 +18,16 @@
 import os
 import re
 from collections import namedtuple
-from warnings import warn
 from os.path import join
-
+from warnings import warn
 
 from lingua_franca.bracket_expansion import SentenceTreeParser
 from lingua_franca.internal import localized_function, \
     populate_localized_function_dict, get_active_langs, \
-    get_full_lang_code, get_default_lang, get_default_loc, \
-    is_supported_full_lang, _raise_unsupported_language, \
-    UnsupportedLanguageError, NoneLangWarning, InvalidLangWarning, \
+    get_full_lang_code, get_default_loc, \
+    is_supported_full_lang, UnsupportedLanguageError, NoneLangWarning, InvalidLangWarning, \
     FunctionNotLocalizedError
 
-
 _REGISTERED_FUNCTIONS = ("nice_number",
                          "nice_time",
                          "pronounce_number",
@@ -42,9 +39,42 @@
 populate_localized_function_dict("format", langs=get_active_langs())
 
 
-def _translate_word(name, lang=''):
+def _translate_word(name, amount=1, lang=''):
     """ Helper to get word translations
 
+    Args:
+        name (str): Word name. Returned as the default value if not translated
+        amount (int): Amount of that word. Used for pluralization
+        lang (str): Language code, e.g. "en-us"
+
+    Returns:
+        str: translated version of resource name
+    """
+    from lingua_franca.internal import resolve_resource_file
+    if not lang:
+        if lang is None:
+            warn(NoneLangWarning)
+        lang = get_default_loc()
+
+    lang_code = lang if is_supported_full_lang(lang) else get_full_lang_code(lang)
+    filename = resolve_resource_file(join("text", lang_code, "translations.json"))
+
+    if filename:
+        try:
+            with open(filename, 'r', encoding='utf8') as file:
+                translations = json.load(file)
+                return translations[name][get_plural_category(amount, lang=lang)]
+        except Exception:
+            pass
+    return _translate_word_legacy(name + ('s' if amount > 1 else ''), lang)  # fallback to legacy translation
+
+
+def _translate_word_legacy(name, lang=''):
+    """ Legacy helper to get word translations.
+
+    Do not use this function directly. Remove it once
+    all languages are migrated to the new format.
+
     Args:
         name (str): Word name. Returned as the default value if not translated
         lang (str): Language code, e.g. "en-us"
@@ -418,35 +448,23 @@ def nice_duration(duration, lang='', speech=True):
         out = ""
         if days > 0:
             out += pronounce_number(days, lang) + " "
-            if days == 1:
-                out += _translate_word("day", lang)
-            else:
-                out += _translate_word("days", lang)
+            out += _translate_word("day", amount=days, lang=lang)
             out += " "
         if hours > 0:
             if out:
                 out += " "
             out += pronounce_number(hours, lang) + " "
-            if hours == 1:
-                out += _translate_word("hour", lang)
-            else:
-                out += _translate_word("hours", lang)
+            out += _translate_word("hour", amount=hours, lang=lang)
         if minutes > 0:
             if out:
                 out += " "
             out += pronounce_number(minutes, lang) + " "
-            if minutes == 1:
-                out += _translate_word("minute", lang)
-            else:
-                out += _translate_word("minutes", lang)
+            out += _translate_word("minute", amount=minutes, lang=lang)
         if seconds > 0:
             if out:
                 out += " "
             out += pronounce_number(seconds, lang) + " "
-            if seconds == 1:
-                out += _translate_word("second", lang)
-            else:
-                out += _translate_word("seconds", lang)
+            out += _translate_word("second", amount=seconds, lang=lang)
     else:
         # M:SS, MM:SS, H:MM:SS, Dd H:MM:SS format
         out = ""
@@ -489,7 +507,7 @@ def join_list(items, connector, sep=None, lang=''):
     else:
         sep += " "
     return (sep.join(str(item) for item in items[:-1]) +
-            " " + _translate_word(connector, lang) +
+            " " + _translate_word(connector, lang=lang) +
             " " + items[-1])
 
 
diff --git a/lingua_franca/res/text/en-us/and.word b/lingua_franca/res/text/en-us/and.word
deleted file mode 100644
index c51107c2..00000000
--- a/lingua_franca/res/text/en-us/and.word
+++ /dev/null
@@ -1 +0,0 @@
-and
\ No newline at end of file
diff --git a/lingua_franca/res/text/en-us/day.word b/lingua_franca/res/text/en-us/day.word
deleted file mode 100644
index 0c303a41..00000000
--- a/lingua_franca/res/text/en-us/day.word
+++ /dev/null
@@ -1 +0,0 @@
-day
\ No newline at end of file
diff --git a/lingua_franca/res/text/en-us/days.word b/lingua_franca/res/text/en-us/days.word
deleted file mode 100644
index 5eb8de30..00000000
--- a/lingua_franca/res/text/en-us/days.word
+++ /dev/null
@@ -1 +0,0 @@
-days
\ No newline at end of file
diff --git a/lingua_franca/res/text/en-us/hour.word b/lingua_franca/res/text/en-us/hour.word
deleted file mode 100644
index a13960e9..00000000
--- a/lingua_franca/res/text/en-us/hour.word
+++ /dev/null
@@ -1 +0,0 @@
-hour
\ No newline at end of file
diff --git a/lingua_franca/res/text/en-us/hours.word b/lingua_franca/res/text/en-us/hours.word
deleted file mode 100644
index 62c6decf..00000000
--- a/lingua_franca/res/text/en-us/hours.word
+++ /dev/null
@@ -1 +0,0 @@
-hours
\ No newline at end of file
diff --git a/lingua_franca/res/text/en-us/minute.word b/lingua_franca/res/text/en-us/minute.word
deleted file mode 100644
index 50bc2f27..00000000
--- a/lingua_franca/res/text/en-us/minute.word
+++ /dev/null
@@ -1 +0,0 @@
-minute
\ No newline at end of file
diff --git a/lingua_franca/res/text/en-us/minutes.word b/lingua_franca/res/text/en-us/minutes.word
deleted file mode 100644
index cde6523a..00000000
--- a/lingua_franca/res/text/en-us/minutes.word
+++ /dev/null
@@ -1 +0,0 @@
-minutes
\ No newline at end of file
diff --git a/lingua_franca/res/text/en-us/or.word b/lingua_franca/res/text/en-us/or.word
deleted file mode 100644
index c4fced5f..00000000
--- a/lingua_franca/res/text/en-us/or.word
+++ /dev/null
@@ -1 +0,0 @@
-or
\ No newline at end of file
diff --git a/lingua_franca/res/text/en-us/second.word b/lingua_franca/res/text/en-us/second.word
deleted file mode 100644
index 2147e418..00000000
--- a/lingua_franca/res/text/en-us/second.word
+++ /dev/null
@@ -1 +0,0 @@
-second
\ No newline at end of file
diff --git a/lingua_franca/res/text/en-us/seconds.word b/lingua_franca/res/text/en-us/seconds.word
deleted file mode 100644
index 729866f9..00000000
--- a/lingua_franca/res/text/en-us/seconds.word
+++ /dev/null
@@ -1 +0,0 @@
-seconds
\ No newline at end of file
diff --git a/lingua_franca/res/text/en-us/translations.json b/lingua_franca/res/text/en-us/translations.json
new file mode 100644
index 00000000..f6a6bb33
--- /dev/null
+++ b/lingua_franca/res/text/en-us/translations.json
@@ -0,0 +1,24 @@
+{
+  "day": {
+    "one": "day",
+    "other": "days"
+  },
+  "hour": {
+    "one": "hour",
+    "other": "hours"
+  },
+  "minute": {
+    "one": "minute",
+    "other": "minutes"
+  },
+  "second": {
+    "one": "second",
+    "other": "seconds"
+  },
+  "and": {
+    "one": "and"
+  },
+  "or": {
+    "one": "or"
+  }
+}
diff --git a/lingua_franca/res/text/sl-si/and.word b/lingua_franca/res/text/sl-si/and.word
deleted file mode 100644
index f087d891..00000000
--- a/lingua_franca/res/text/sl-si/and.word
+++ /dev/null
@@ -1 +0,0 @@
-in
\ No newline at end of file
diff --git a/lingua_franca/res/text/sl-si/day.word b/lingua_franca/res/text/sl-si/day.word
deleted file mode 100644
index dc816d94..00000000
--- a/lingua_franca/res/text/sl-si/day.word
+++ /dev/null
@@ -1 +0,0 @@
-dan
\ No newline at end of file
diff --git a/lingua_franca/res/text/sl-si/days.word b/lingua_franca/res/text/sl-si/days.word
deleted file mode 100644
index 7b0e614a..00000000
--- a/lingua_franca/res/text/sl-si/days.word
+++ /dev/null
@@ -1 +0,0 @@
-dni
\ No newline at end of file
diff --git a/lingua_franca/res/text/sl-si/hour.word b/lingua_franca/res/text/sl-si/hour.word
deleted file mode 100644
index fa6c4e16..00000000
--- a/lingua_franca/res/text/sl-si/hour.word
+++ /dev/null
@@ -1 +0,0 @@
-ura
\ No newline at end of file
diff --git a/lingua_franca/res/text/sl-si/hours.word b/lingua_franca/res/text/sl-si/hours.word
deleted file mode 100644
index 873003f7..00000000
--- a/lingua_franca/res/text/sl-si/hours.word
+++ /dev/null
@@ -1 +0,0 @@
-ur
\ No newline at end of file
diff --git a/lingua_franca/res/text/sl-si/minute.word b/lingua_franca/res/text/sl-si/minute.word
deleted file mode 100644
index 02810dfe..00000000
--- a/lingua_franca/res/text/sl-si/minute.word
+++ /dev/null
@@ -1 +0,0 @@
-minuta
\ No newline at end of file
diff --git a/lingua_franca/res/text/sl-si/minutes.word b/lingua_franca/res/text/sl-si/minutes.word
deleted file mode 100644
index 4b98366b..00000000
--- a/lingua_franca/res/text/sl-si/minutes.word
+++ /dev/null
@@ -1 +0,0 @@
-minut
\ No newline at end of file
diff --git a/lingua_franca/res/text/sl-si/or.word b/lingua_franca/res/text/sl-si/or.word
deleted file mode 100644
index 784f9000..00000000
--- a/lingua_franca/res/text/sl-si/or.word
+++ /dev/null
@@ -1 +0,0 @@
-ali
\ No newline at end of file
diff --git a/lingua_franca/res/text/sl-si/second.word b/lingua_franca/res/text/sl-si/second.word
deleted file mode 100644
index ef210e25..00000000
--- a/lingua_franca/res/text/sl-si/second.word
+++ /dev/null
@@ -1 +0,0 @@
-sekunda
\ No newline at end of file
diff --git a/lingua_franca/res/text/sl-si/seconds.word b/lingua_franca/res/text/sl-si/seconds.word
deleted file mode 100644
index 300f8e50..00000000
--- a/lingua_franca/res/text/sl-si/seconds.word
+++ /dev/null
@@ -1 +0,0 @@
-sekund
\ No newline at end of file
diff --git a/lingua_franca/res/text/sl-si/translations.json b/lingua_franca/res/text/sl-si/translations.json
new file mode 100644
index 00000000..a8d09bb5
--- /dev/null
+++ b/lingua_franca/res/text/sl-si/translations.json
@@ -0,0 +1,32 @@
+{
+  "day": {
+    "one": "dan",
+    "two": "dneva",
+    "few": "dnevi",
+    "other": "dni"
+  },
+  "hour": {
+    "one": "ura",
+    "two": "uri",
+    "few": "ure",
+    "other": "ur"
+  },
+  "minute": {
+    "one": "minuta",
+    "two": "minuti",
+    "few": "minute",
+    "other": "minut"
+  },
+  "second": {
+    "one": "sekunda",
+    "two": "sekundi",
+    "few": "sekunde",
+    "other": "sekund"
+  },
+  "and": {
+    "one": "in"
+  },
+  "or": {
+    "one": "ali"
+  }
+}
diff --git a/test/test_format_sl.py b/test/test_format_sl.py
index f3182785..e044d2d8 100644
--- a/test/test_format_sl.py
+++ b/test/test_format_sl.py
@@ -530,13 +530,10 @@ def test_nice_year(self):
 #                print(nice_year(dt, lang=lang))
 
     def test_nice_duration(self):
-        # TODO implement better plural support for nice_duration
-        # Correct results are in comments
-
         self.assertEqual(nice_duration(1), "ena sekunda")
-        self.assertEqual(nice_duration(2), "dve sekund")  # dve sekundi
-        self.assertEqual(nice_duration(3), "tri sekund")  # tri sekunde
-        self.assertEqual(nice_duration(4), "štiri sekund")  # štiri sekunde
+        self.assertEqual(nice_duration(2), "dve sekundi")
+        self.assertEqual(nice_duration(3), "tri sekunde")
+        self.assertEqual(nice_duration(4), "štiri sekunde")
         self.assertEqual(nice_duration(5), "pet sekund")
         self.assertEqual(nice_duration(6), "šest sekund")