diff --git a/soundchanger/change.py b/soundchanger/change.py
index a9c7f79..a63e8eb 100644
--- a/soundchanger/change.py
+++ b/soundchanger/change.py
@@ -1,18 +1,45 @@
 import re
 
 
-def apply(change, string, categories={}, apply=True, zero_characters=['∅']):
+def apply(changes, strings, categories={}, apply=True, zero_characters=['∅']):
     """Apply a sound change to a given string"""
 
     if not apply:
-        return string
+        return strings
+    
+    if isinstance(changes, str):
+        changes = [changes]
+    
+    return_str = isinstance(strings, str)
+    if isinstance(strings, str):
+        strings = [strings]
 
-    # Check validity of change
+    for change in changes:
+        validate_change(change)
+        change = convert_change_to_regex(change, categories=categories, zero_characters=zero_characters)
+
+        original, change_to, before, after = split_change(change)
+
+        pattern = f"({before})({original})({after})"
+        last_group_index = pattern.count('(') - after.count('(')
+        replacement = f"\\1{change_to}\\{last_group_index}"
+
+        for i, string in enumerate(strings):
+            strings[i] = re.sub(pattern, replacement, f"#{string}#").strip('#')
+    
+    if return_str:
+        return strings[0]
+    return strings
+
+
+def validate_change(change):
     if change.count('>') != 1:
         raise ValueError(f"Change {change} is not a valid sound change. (Missing character '>')")
     if change.count('/') > 1:
         raise ValueError(f"Change {change} is not a valid sound change. (More than one '/' character)")
 
+
+def convert_change_to_regex(change, categories, zero_characters):
     # Prepare change for regex
     for k, v in {' ': '', '{': '(', '}': ')', ',': '|'}.items():
         change = change.replace(k, v)
@@ -23,7 +50,15 @@ def apply(change, string, categories={}, apply=True, zero_characters=['∅']):
         change = re.sub(f'((?<=,){k}|{k}(?=,))', '|'.join(v), change)
         # Replacements of categories anywhere else
         change = change.replace(k, '('+'|'.join(v)+')')
+    
+    # Remove zero characters
+    for char in zero_characters:
+        change = change.replace(char, '')
+    
+    return change
 
+
+def split_change(change):
     if '/' in change:
         change, environment = change.split('/')
     else:
@@ -40,13 +75,5 @@ def apply(change, string, categories={}, apply=True, zero_characters=['∅']):
 
     if not original:
         raise ValueError(f"Nothing to change from.")
-
-    # Remove zero characters
-    for char in zero_characters:
-        change_to = change_to.replace(char, '')
-
-    pattern = f"({before})({original})({after})"
-    last_group_index = pattern.count('(') - after.count('(')
-    replacement = f"\\1{change_to}\\{last_group_index}"
-
-    return re.sub(pattern, replacement, f"#{string}#").strip('#')
+    
+    return (original, change_to, before, after)
\ No newline at end of file
diff --git a/tests/test_change.py b/tests/test_change.py
index fba8203..0399f24 100644
--- a/tests/test_change.py
+++ b/tests/test_change.py
@@ -41,9 +41,7 @@ def test_complex_environment():
     inputs =  ['pana', 'pina', 'puna', 'pama', 'pima', 'puma']
     outputs = ['pana', 'hina', 'huna', 'pama', 'hima', 'huma']
     for string, output in zip(inputs, outputs):
-        assert apply(
-                change='p>h/#_{u,i}Na#',
-                string=string,
+        assert apply('p>h/#_{u,i}Na#', string,
                 categories={'N': 'nm'}
             ) == output
 
@@ -54,7 +52,7 @@ def test_complex_group_and_categories():
         'N': 'mn',
         }) == 'pani'
 
-def test_with_complex_group_and_categories_and_digraphs():
+def test_complex_group_and_categories_and_digraphs():
     assert apply('u>o/#V{ts,pf,t}_k{V,e,o}#', 'atsuka', categories={
         'V': ['a', 'i', 'u']
     }) == 'atsoka'
@@ -65,13 +63,28 @@ def test_with_complex_group_and_categories_and_digraphs():
         'V': ['a', 'i', 'u']
     }) == 'matsuka'
 
+def test_change_from_category():
+    assert apply('V>o', 'tatiru', categories={
+        'V': 'aiu'
+    }) == 'totoro'
+
+def test_list_and_str_inputs():
+    assert apply('a>b', 'cad') == 'cbd'
+    assert apply(['a>b'], 'cad') == 'cbd'
+    assert apply('a>b', ['cad']) == ['cbd']
+    assert apply(['a>b'], ['cad']) == ['cbd']
+
 def test_multiple_changes():
     string = 'pana'
     for change in ['p>f', 'n>m/fa_']:
         string = apply(change, string)
     assert string == 'fama'
+    assert apply(['p>f', 'n>m/fa_'], string) == 'fama'
 
-def test_change_from_category():
-    assert apply('V>o', 'tatiru', categories={
-        'V': 'aiu'
-    }) == 'totoro'
+def test_multiple_strings():
+    assert apply('p>f', ['pana', 'pune']) == [
+        'fana', 'fune'
+    ]
+
+def test_multiple_changes_and_strings():
+    assert apply(['p>f', 'f>h/#_a'], ['pana', 'pune']) == ['hana', 'fune']