diff --git a/codespell_lib/data/dictionary_en-GB_to_en-US.txt b/codespell_lib/data/dictionary_en-GB_to_en-US.txt
index 79aad073ac..8cfea89100 100644
--- a/codespell_lib/data/dictionary_en-GB_to_en-US.txt
+++ b/codespell_lib/data/dictionary_en-GB_to_en-US.txt
@@ -1,5 +1,10 @@
 acknowledgement->acknowledgment
 acknowledgements->acknowledgments
+aesthetic->esthetic
+aesthetically->esthetically
+aesthetician->esthetician
+aestheticians->estheticians
+aesthetics->esthetics
 aggrandise->aggrandize
 aggrandised->aggrandized
 aggrandisement->aggrandizement
@@ -38,6 +43,7 @@ bastardising->bastardizing
 behaviour->behavior
 behavioural->behavioral
 behaviours->behaviors
+biassed->biased
 cancelled->canceled
 cancelling->canceling
 capitalisation->capitalization
@@ -68,6 +74,7 @@ characterising->characterizing
 cognisant->cognizant
 colour->color
 colouration->coloration
+colourations->colorations
 coloured->colored
 colourful->colorful
 colourfully->colorfully
@@ -84,6 +91,7 @@ crystallise->crystallize
 crystallised->crystallized
 crystallises->crystallizes
 crystallising->crystallizing
+customisable->customizable
 customisation->customization
 customise->customize
 customised->customized
@@ -102,6 +110,7 @@ demonised->demonized
 demonises->demonizes
 demonising->demonizing
 dialogue->dialog
+dialogues->dialogs
 digitisation->digitization
 digitise->digitize
 digitised->digitized
@@ -113,6 +122,8 @@ dishonourable->dishonorable
 dishonoured->dishonored
 dishonouring->dishonoring
 dishonours->dishonors
+doughnut->donut
+doughnuts->donuts
 economise->economize
 emphasise->emphasize
 emphasised->emphasized
@@ -148,6 +159,9 @@ finalises->finalizes
 finalising->finalizing
 flavour->flavor
 flavours->flavors
+focussed->focused
+focusses->focuses
+focussing->focusing
 formalisation->formalization
 formalise->formalize
 formalised->formalized
@@ -165,9 +179,11 @@ grey->gray
 greyed->grayed
 greyish->grayish
 greys->grays
+greyscale->grayscale
 haemorrhage->hemorrhage
 haemorrhaged->hemorrhaged
 haemorrhages->hemorrhages
+haemorrhagic->hemorrhagic
 haemorrhaging->hemorrhaging
 honour->honor
 honoured->honored
@@ -201,6 +217,8 @@ labelling->labeling
 labour->labor
 laboured->labored
 labours->labors
+lambast->lambaste
+lambasts->lambastes
 legalisation->legalization
 legalise->legalize
 legalised->legalized
@@ -208,7 +226,9 @@ legalises->legalizes
 legalising->legalizing
 leukaemia->leukemia
 licence->license
+licenced->licensed
 licences->licenses
+licencing->licensing
 litre->liter
 litres->liters
 localise->localize
@@ -216,7 +236,9 @@ localised->localized
 localises->localizes
 localising->localizing
 manoeuvre->maneuver
+manoeuvred->maneuvered
 manoeuvres->maneuvers
+manoeuvring->maneuvering
 marshalled->marshaled
 marshalling->marshaling
 maximisation->maximization
@@ -264,6 +286,8 @@ normalised->normalized
 normalises->normalizes
 normalising->normalizing
 ochre->ocher
+ochreous->ocherous
+ochrey->ochery
 optimisation->optimization
 optimisations->optimizations
 optimise->optimize
@@ -313,6 +337,11 @@ randomise->randomize
 randomised->randomized
 randomises->randomizes
 randomising->randomizing
+rasterisation->rasterization
+rasterise->rasterize
+rasterised->rasterized
+rasterises->rasterizes
+rasterising->rasterizing
 rationalise->rationalize
 rationalised->rationalized
 rationalising->rationalizing
@@ -325,6 +354,9 @@ recognise->recognize
 recognised->recognized
 recognises->recognizes
 recognising->recognizing
+refocussed->refocused
+refocusses->refocuses
+refocussing->refocusing
 regularisation->regularization
 regularise->regularize
 regularised->regularized
@@ -338,9 +370,11 @@ reorganised->reorganized
 reorganises->reorganizes
 reorganising->reorganizing
 rigour->rigor
+sanitisation->sanitization
 sanitise->sanitize
 sanitised->sanitized
 sanitiser->sanitizer
+sanitisers->sanitizers
 sanitises->sanitizes
 sanitising->sanitizing
 sceptical->skeptical
@@ -386,6 +420,8 @@ symbolising->symbolizing
 synchronisation->synchronization
 synchronise->synchronize
 synchronised->synchronized
+synchroniser->synchronizer
+synchronisers->synchronizers
 synchronises->synchronizes
 synchronising->synchronizing
 totalled->totaled
@@ -393,6 +429,7 @@ totalling->totaling
 unauthorised->unauthorized
 unfavourable->unfavorable
 unfavourably->unfavorably
+uninitialised->uninitialized
 unorganised->unorganized
 unrecognisable->unrecognizable
 unrecognised->unrecognized
@@ -402,6 +439,12 @@ utilise->utilize
 utilised->utilized
 utilises->utilizes
 utilising->utilizing
+vectorisation->vectorization
+vectorisations->vectorizations
+vectorise->vectorize
+vectorised->vectorized
+vectorises->vectorizes
+vectorising->vectorizing
 virtualisation->virtualization
 visualisation->visualization
 visualisations->visualizations
@@ -410,3 +453,4 @@ visualised->visualized
 visualiser->visualizer
 visualises->visualizes
 visualising->visualizing
+writeable->writable
diff --git a/codespell_lib/tests/data/en_GB-additionnal.wordlist b/codespell_lib/tests/data/en_GB-additionnal.wordlist
new file mode 100644
index 0000000000..ce88229aba
--- /dev/null
+++ b/codespell_lib/tests/data/en_GB-additionnal.wordlist
@@ -0,0 +1,35 @@
+aesthetician
+aestheticians
+biassed
+colourations
+customisable
+dialogues
+focussed
+focusses
+focussing
+greyscale
+haemorrhagic
+lambast
+lambasts
+licenced
+licencing
+ochreous
+ochrey
+rasterisation
+rasterise
+rasterised
+rasterises
+rasterising
+refocussed
+refocusses
+refocussing
+sanitisation
+synchroniser
+synchronisers
+vectorisation
+vectorisations
+vectorise
+vectorised
+vectorises
+vectorising
+writeable
diff --git a/codespell_lib/tests/data/en_US-additionnal.wordlist b/codespell_lib/tests/data/en_US-additionnal.wordlist
new file mode 100644
index 0000000000..8d761ed229
--- /dev/null
+++ b/codespell_lib/tests/data/en_US-additionnal.wordlist
@@ -0,0 +1,26 @@
+colorations
+customizable
+dialogs
+donut
+esthetic
+esthetically
+esthetician
+estheticians
+esthetics
+grayscale
+ocherous
+ochery
+rasterization
+rasterize
+rasterized
+rasterizes
+rasterizing
+sanitization
+synchronizer
+synchronizers
+vectorization
+vectorizations
+vectorize
+vectorized
+vectorizes
+vectorizing
diff --git a/codespell_lib/tests/test_dictionary.py b/codespell_lib/tests/test_dictionary.py
index a81643ec36..fbd3b5d7a6 100644
--- a/codespell_lib/tests/test_dictionary.py
+++ b/codespell_lib/tests/test_dictionary.py
@@ -14,9 +14,14 @@
 try:
     import aspell  # type: ignore[import]
 
+    _test_data_dir = op.join(op.dirname(__file__), "..", "tests", "data")
     for lang in supported_languages:
-        spellers[lang] = aspell.Speller("lang", lang)
-except Exception as exp:  # probably ImportError, but maybe also language
+        _wordlist = op.join(_test_data_dir, f"{lang}-additionnal.wordlist")
+        if op.isfile(_wordlist):
+            spellers[lang] = aspell.Speller(("lang", lang), ("wordlists", _wordlist))
+        else:
+            spellers[lang] = aspell.Speller("lang", lang)
+except ImportError as exp:
     if os.getenv("REQUIRE_ASPELL", "false").lower() == "true":
         raise RuntimeError(
             "Cannot run complete tests without aspell when "
@@ -259,6 +264,7 @@ def test_error_checking_in_aspell(
     ("dictionary.txt", "dictionary_rare.txt"),
     ("dictionary.txt", "dictionary_usage.txt"),
     ("dictionary_code.txt", "dictionary_rare.txt"),
+    ("dictionary_rare.txt", "dictionary_en-GB_to_en-US.txt"),
     ("dictionary_rare.txt", "dictionary_usage.txt"),
 }