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USPTO Trademark Search: Sound Matching

Rachael Dickson | May 11, 2024
3 min read

Rachael Dickson is a Trademark Attorney at Lloyd & Mousilli and Catalytic Law. Rachael worked as an examining attorney at the USPTO from 2017-2021, where she was awarded a 2020 Customer Service Award. While at the USPTO, Rachael was part of a work group which specialized in reviewing applications to register trademarks with cannabis goods and services. Rachael directed the Intellectual Property and Entrepreneurship Clinic at Suffolk University School of Law as a visiting assistant professor from Fall 2022 – Spring 2024. Her legal article, High Hopes: Cannabis Trademarks at the USPTO, is forthcoming in the Ohio State Technology Law Journal in 2025.

Here’s a helpful phonetic equivalents chart to help you perform more effective and efficient trademark searches!

What are phonetic equivalents (also known as sound matching)?

Phonetic equivalents (aka sound matching) are used to ensure that you don’t miss possible homophones  in your search. A homophone is a word that sounds the same as another word but has a different spelling. Even though homophones look different, they can potentially cause consumer confusion in the marketplace.

Let’s say that your client wanted to apply to register FOR SON for baseball hats. If you just searched these exact words on the trademark register and didn’t find any conflicts in Class 25 or 35, you might think the mark was good to go! However, such a search could easily miss a prior registration for FOUR SUN for t-shirts, which would definitely be cited against your client’s trademark in a §2(d) Likelihood of Confusion refusal.

Using phonetic equivalents in your search accounts for homophones and alternative spellings. You can use the sound matching chart to look up and replace, if necessary, each letter with the appropriate punctuation and/or letters.

All vowels will be replaced, as vowels can be combined in many different ways to represent similar sounds. Consonants that could sound like other consonants will be replaced.

For example, if you would like to search all live records which have the word CHAT in the wordmark, you’ll want to ensure that you’re searching for all the ways CHAT could be written using alternative spellings.

The sound of the first letter, the soft “c”, could also be represented by S or perhaps Z. You can represent all those possibilities with: [csz]. This tells the system that this one character could be C, S, or Z. The second letter “h” and the fourth letter “t” have no phonetic equivalents, so we can leave those as they are.

The third letter “a”, is a vowel. Generally, it’s best practice to start a search off with allowing for all vowel possibilities at once, as some vowels can sound alike (for example, “i” and “y”), and variations of words sometimes incorporate different vowels as well. You can represent all vowels in a search with: [aeiou].

The USPTO also recommends starting off a search by allowing for the possibility that any 1 character might be replaced by 1-2 characters. You can represent this by using numbers paired with curly brackets to show the number of times you’d like a prior component matched. This can be an exact number, or a minimum and maximum number of occurrences. For example, [gj]{2} matches gg, gj, jg, or jj. [ae]{1,2} matches a, e, aa, ae, ea, or ee.

RegEx Tip: You’ll need to add in a forward slash / before and after when you’re adding in sound matching, truncation, or any wildcard symbols.

  • Example: Let’s search my first name – “Rachael”

Remember, you’re going to want to use the basic field code CM: (which runs a search through the word, translation, and pseudo mark fields) and AND LD:true (which specifies that you’re only looking for live marks) to start.

  • CM:/r[aeiouy]{1,2}[scz]{1,2}h[aeiouy]{1,2}l/ AND LD:true
  • Equivalent to r{v1:2}{“szcx”}h{v1:2}l[bi,ti] not dead[ld]

Caution: This chart tries to cover the vast majority of homophonic sounds, but it is likely impossible to cover every single sound out there on one chart. This chart is likely particularly lacking when it comes to names and sounds originating in non-Romantic languages. For example, this chart is unable to account for the sounds present in the Gaelic name Siobhan, which is pronounced shiv-AWN or the Chinese word Qi (which is pronounced chee). I would love to develop a crowd-sourced sound matching chart in the future to remedy this problem! In the meantime, when you’re searching a word, try to also think of any other words that sound like it and make sure those are represented in your search, even if it’s not explicitly listed on the chart.

For more tips on conducting searches using the USPTO’s new Trademark Search, click here.

Letter What to Search
a [aeiouy]{1,2}
b b
c If k sound: [ckqx]{1,2}
If sound: [scz]{1,2}
d d
e [aeiouy]{1,2}
f [fph]{1,2}
g If hard g sound (thing, gorilla): g
If soft sound (germ, dodge): d{0,1}[gjy]
h h
i [aeiouy]{1,2}
j d{0,1}[gj]
k [ckqx]{1,2}
l l
m m
n n
o [aeiouy]{1,2}
p p
q [ckqx]{1,2}
r r
s [scz]{1,2}
t t
u [aeiouy]{1,2}
v v
w w
x  [ckqx]{1,2}
y If used as a consonant: y
If used as a vowel: [aeiouy]{1,2}
z [scz]{1,2}
ph [fph]{1,2}
tion (ex. action, fashion) [scth]{0,3}[aeiouy]{1,2}n
long i/e (ex. sighlye) [iey]{1,2}

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