The Most Difficult Sounds to Pronounce in English

For non-native speakers, English is tricky to master due to pronunciation inconsistencies & irregularities. Here are some of the most difficult sounds to say correctly.

By   Ofer HEADSHOT Ofer Ronen   in   Accents   03/13/25

Share on Twitter Share on LinkedIn Share via Email Copy Link Link copied!

English is spoken practically all over the world, which is quite notable considering how difficult the language can be to master. Not only is the grammar rife with complex exceptions and irregularities, but there’s an abundance of pronunciation variations.  To further complicate matters, English has borrowed from a number of other languages, resulting in words, which have multiple meanings and nuances.

Then, there’s the wide array of accents and dialects, rendering the language difficult for many nonnative speakers to grasp and use effectively. Call center agents — and customers — can attest to this, as many representatives are located offshore who speak English with heavy accents that can be difficult for native Americans to understand. 

That’s why more and more companies are signing up for AI accent smoothing platforms like Tomato.ai. These can make offshore agents sound more like onshore agents to heighten customer trust. With that in mind, let’s look at the most difficult sounds to pronounce in English, and more.

A man's face looking unsure as thought bubbles with difficult English words fill his head: rural, squirrel, sixth.

Speaking is Problematic 

English can be a challenge for nonnative speakers to learn due to inconsistent pronunciation and spelling rules. Because the language borrowed heavily from multiple languages, some words with the same spelling have multiple pronunciations, linguists point out. And depending on the context, the same pronunciation can have varying meanings. Additionally, English has stresses, intonation patterns and accents that can alter meaning.

Vast Vocabulary 

More than one million words strong, English is one of the world’s most extensive languages. But that’s exactly what can vex nonnative speakers since vocabulary is any language’s foundation. That means that without a good understanding of English words, speaking, writing, reading, and listening can be a struggle. Determining the proper context can also be a challenge, as words can have multiple meanings.

Nonnative speakers also must contend with many slang terms, phrasal verbs, and idioms in English.

Grammar Gripes

The many irregular verbs and complex rules in English can pose problems for those seeking English mastery. All that borrowing from other languages caused grammar to evolve over time, resulting in a ton of variations and exceptions. 

Plus, there are some English words that have the same spelling or pronunciation, or both — and some have multiple meanings. The use of prepositions, articles, and verb tenses can also cause learner confusion.

Exceptions Abound

Another big problem with learning English is all the exceptions. Not all verbs add “-ed” at the end to form the past tense, for example. And not all plurals merely call for adding an “s.” There’s “children” for “child,” for instance, and “teeth” for more than one “tooth.”

Then there are those confusing homophones such as “their,” “there,” and “they’re,” all of which have different meanings but are pronounced the same.

A Plethora of Slangs and Idioms

Slangs and idioms in English can be problematic because they commonly use figurative language that can possess a meaning that’s different from what the words suggest. Not only that, but the words’ origins may be unclear.

The use of slang terms can also vary a great deal, depending on context and region. And because they’re constantly created, slang terms can be difficult to keep up with.

The Hardest Sounds to Pronounce

While the following sounds are not difficult for all English learners, they are generally problematic for most. It largely depends on the mother tongue’s influence.

The “V” and “W” sounds. 

The “V” is a “voiced” sound, which means the vocal cords vibrate with pronunciation. 

German speakers in particular tend to have problems with these two letters because there is no “w” sound in German. Thus, “well” is “vell” and “welcome” is “velcome,” for example.

The “th” sound. 

There can be two ways to pronounce this sound, which can be tricky by itself. The first one is voiced, as in “this” and “father.” Examples of the unvoiced pronunciation include “thanks,” “three,” and “mouth.”

There is no “th” sound in French, so French speakers often supplant it with the letters “s,” “f,” or “z.” So, “Thursday” can become “fursday,” and “them” can be pronounced “zem.”

Russian speakers, too, can experience problems with “th” and may pronounce it as the “z” sound.

The “b” and “v” sounds. 

The letter “v” in Spanish is pronounced the same as the voiced sound “b.” Thus, Spanish speakers will often say “bery” for “very,” and “telebision” for “television.”

The “ed” sound. 

The “ed” sound in past tense and past participle has multiple pronunciations, rendering it among the language’s most difficult sounds. Note how the pronunciation of “needed” and “divided” compares to “cooked” or “pushed.”  

Brazilian Portuguese speakers will usually add a syllable and pronounce words ending in “ed” with the “id” sound.

The “r” and “l” sounds. 

Korean, Japanese, and Chinese learners tend to have a tough time with these letters, largely because their native language lacks similar sounds.

The Takeaway

English is the language of international communication and is the official language of 67 countries and 27 non-sovereign entities. Including nonnative speakers, it’s the world’s most-spoken language.

Yet, it can be a pain to learn, what with the varying pronunciation rules, expansive vocabulary, irregular grammar, and numerous exceptions. Then there are all those slang words and idioms to parse and keep track of.

Given all that, it’s no wonder that many U.S. companies are facing issues with their offshore call centers. To that end, many forward thinking call centers are employing AI accent smoothing platforms like the one offered by Tomato.ai. With this GenAI voice technology, agent performance is improved by real-time speech augmentation that can potentially improve the corporate bottom line.

By Ofer Ronen in Accents 03/13/25

Share on Twitter Share on LinkedIn Share via Email Copy Link Link copied!

Popular Blog PostsSee all posts

Accent translation improves call center customer service by removing language barriers that often result in misunderstandings & less efficient conversations.

A recently released survey found the UK’s most attractive accents. Here are the results.

Learn about the top accents which Americans find favorable, and why they like those accents

Serving as a call center agent requires a specific set of skills & certain personality traits. Here’s what you need to know to land a call center job in India.

Canada has a wide variety of accents, reflecting the country's diversity in both geography & population. Learn more about these regional accents and what makes them unique.