How Translation Memory Works and Why It Matters
If you commission translations regularly, you have almost certainly benefited from translation memory without knowing it. Translation memory (TM) is one of the most important technologies in the professional translation industry, quietly working behind the scenes to improve consistency, reduce costs, and accelerate delivery — yet most clients have only a vague understanding of what it does and how it works.
This article explains translation memory in clear, practical terms so you can make informed decisions about your translation investments and get more value from your language service provider.
For professional translation services that leverage translation memory and other technologies to deliver consistent, cost-effective results, explore Ecrivus International’s technology-driven translation workflow. For a broad overview of the translation industry, visit our complete guide to translation services.
What Is Translation Memory?
Translation memory is a database that stores pairs of text segments — the original (source) text alongside its approved translation (target text). Each pair is called a “translation unit.” As a translator works on a new document, the translation memory system automatically compares each new source segment against the database and presents any relevant matches.
Think of it as a searchable archive of every translation decision ever approved for your content. Instead of translating the same sentence from scratch every time it appears, the translator can leverage previous work — ensuring consistency and saving time.
How Segments Work
Translation memory systems break text into segments, typically at the sentence level. When a translator works on a new segment, the system searches the database for matches:
- Exact match (100%): The new source segment is identical to a previously translated segment. The system presents the stored translation, which the translator can accept as-is or modify.
- Fuzzy match (typically 70-99%): The new source segment is similar but not identical to a stored segment. The system highlights the differences, and the translator adapts the previous translation rather than starting from scratch.
- No match (below threshold): The new source segment has no useful match in the database. The translator translates it from scratch, and the new translation unit is added to the memory for future use.
For example, if your translation memory contains:
Source: “This product must be stored at temperatures between 2°C and 8°C.” Target: “Dit product moet worden bewaard bij temperaturen tussen 2 °C en 8 °C.”
And a new document contains:
“This product must be stored at temperatures between 5°C and 25°C.”
The system would flag this as a fuzzy match (perhaps 85%), present the previous translation, and highlight the temperature values that need updating. The translator changes “2 °C en 8 °C” to “5 °C en 25 °C” and confirms — a much faster process than translating from scratch.
The Benefits of Translation Memory
1. Consistency
Consistency is arguably the most important benefit of translation memory, especially for organizations that produce large volumes of content over time or across multiple departments.
Without TM, different translators working on different projects might translate the same term or phrase differently. Product names might be rendered inconsistently, standard disclaimers might vary in wording, and technical terminology might shift from document to document.
Translation memory ensures that once a term, phrase, or sentence has been approved, it is reused consistently across all future projects. This is particularly valuable for:
- Brand language: Ensuring that your brand voice and key messages are consistent across all languages
- Technical terminology: Maintaining consistent use of product names, component names, and technical terms across manuals, data sheets, and training materials
- Legal language: Preserving established translations of standard contract clauses and legal formulations
- Regulatory content: Ensuring that approved regulatory language is reused precisely
For technical content, where terminology consistency is critical, translation memory works hand-in-hand with the terminology management practices described in our technical translation guide.
2. Cost Reduction
Translation memory reduces costs by eliminating redundant translation work. When a segment has been translated before, the translator does not need to translate it again — and reputable translation agencies pass these savings on to clients through tiered pricing:
- 100% matches and repetitions: Typically charged at 20-30% of the full translation rate
- Fuzzy matches (75-99%): Typically charged at 50-70% of the full rate, depending on the match percentage
- No match (new segments): Charged at the full translation rate
The savings depend on the repetitiveness of your content. For highly repetitive content (updated versions of product manuals, regulatory submissions with standardized sections, annual report translations), savings of 30-60% compared to translating from scratch are common. For entirely new, non-repetitive content (a novel marketing campaign, a unique thought leadership article), TM savings will be minimal.
3. Faster Turnaround
When translators can leverage previous translations instead of starting from scratch, projects move faster. Exact matches require only a quick review; fuzzy matches require minor editing rather than full translation. This acceleration is particularly valuable for:
- Urgent projects: When time is critical, TM enables faster delivery without sacrificing quality
- Large-volume projects: Translating 50,000 words of updated product documentation is much faster when 60% of the content matches the previous version
- Simultaneous multilingual releases: When content must be published in multiple languages at the same time
4. Knowledge Preservation
Translation memory preserves institutional knowledge about how your content should be translated. If a key translator leaves or your translation partner changes, the TM retains all previous translation decisions. New translators can leverage this accumulated knowledge rather than starting from scratch.
This is particularly important for long-term content programs where consistency with previously published translations matters.
How Translation Memory Fits Into the Translation Workflow
Translation memory is one component of a broader set of technologies known as Computer-Assisted Translation (CAT) tools. These tools also include:
- Terminology databases: Glossaries of approved terms that are presented to translators as they work, ensuring consistent use of key terminology
- Quality assurance checks: Automated checks for consistency, formatting, and common errors
- Alignment tools: Software that can create translation memory from pairs of previously translated documents (even if they were not originally translated using TM)
- Project management features: Workflow tools for assigning, tracking, and reviewing translation projects
Together, these tools form the technology backbone of professional translation. They augment human translators — they do not replace them. The translator makes all final decisions about quality and appropriateness; the tools ensure consistency and efficiency.
Translation Memory vs. Machine Translation
Translation memory is frequently confused with machine translation, but they are fundamentally different technologies:
| Translation Memory | Machine Translation | |
|---|---|---|
| How it works | Retrieves previous human translations from a database | Generates new translations using AI algorithms |
| Source of translations | Previous human-approved translations | Statistical or neural models trained on large datasets |
| Quality guarantee | Matches are previously reviewed and approved | Output requires human review and editing |
| Improvement over time | Grows more valuable as more translations are stored | Improves through model updates and training data |
| Best for | Repetitive content, updates, consistency-critical content | New content with no previous translations, high-volume first drafts |
| Customization | Specific to your content and approved terminology | Can be trained on your data, but remains probabilistic |
In modern translation workflows, translation memory and machine translation often work together. The TM handles segments that have been translated before; machine translation provides initial drafts for new segments that the translator then reviews and refines (a process called post-editing).
Building and Managing Your Translation Memory
Starting from Scratch
If you are commissioning professional translations for the first time, your translation memory starts empty and grows with each project. Every approved translation is stored and becomes available for future use. The more you translate, the more valuable your TM becomes.
Leveraging Existing Translations
If you have previously translated documents that were not produced using TM technology, they can still be used. Translation agencies can “align” existing translations with their source texts to create translation units and populate your TM. This is particularly valuable when switching translation providers — you do not need to lose the investment in previous translations.
TM Ownership
Your translation memory represents a significant intellectual asset. Clarify TM ownership with your translation provider:
- Who owns the TM? In most cases, the client should own the translation memory generated from their content
- Can you export the TM? You should be able to obtain a copy of your TM in standard formats (TMX is the industry standard)
- What happens if you change providers? Your TM should be transferable to a new provider
Reputable translation agencies are transparent about TM ownership and will provide exports upon request.
TM Maintenance
Like any database, translation memory benefits from periodic maintenance:
- Remove outdated entries: When terminology changes, old translations should be updated or removed
- Resolve inconsistencies: If the same source segment has been translated differently in different projects, the best translation should be selected and the others discarded or flagged
- Update for rebranding: When product names, company names, or brand language change, the TM should be updated to reflect current usage
- Segment translations that cross sentence boundaries: Sometimes TM segments need to be split or merged for optimal matching
Discuss your translation memory strategy with Ecrivus International to learn how TM management can improve your multilingual content strategy.
When Translation Memory Provides the Most Value
TM delivers the greatest benefits in specific scenarios:
Product Documentation Updates
When a product is updated and the documentation is revised, much of the content remains unchanged. TM ensures that only the changed sections are re-translated, while unchanged content is reused from the previous version — saving significant time and cost.
Multi-Language Translation
When the same content is translated into many languages, TM benefits multiply. Terminology consistency, cost savings, and turnaround improvements apply across all language pairs.
Regulatory and Compliance Content
Regulatory filings often contain standardized sections that are repeated or updated periodically. TM ensures these sections are translated consistently and efficiently.
Website Content
Websites are continuously updated, with new pages added and existing pages revised. TM ensures that navigation elements, UI text, recurring phrases, and standardized content are translated consistently across all updates. For more on website localization best practices, see our dedicated guide.
Long-Term Content Programs
Organizations that translate content regularly over months and years accumulate increasingly valuable TM assets. The cost per word decreases as more content matches previous translations, and consistency improves as the TM becomes more comprehensive.
Maximizing Your TM Investment
To get the most from translation memory:
- Use the same provider consistently: Your TM grows with each project. Switching providers frequently means starting over (unless you ensure TM portability)
- Write consistently: Consistent source-language writing produces more TM matches. If you use the same phrasing for the same concept, the TM will match more frequently. This is one more reason to invest in source-text quality for technical content
- Provide feedback: When you identify translation improvements, communicate them to your provider so the TM can be updated
- Plan updates strategically: When updating documents, provide the previous version alongside the new version so the TM can identify what has changed
- Protect your TM: Treat your translation memory as a valuable business asset. Ensure it is backed up, that you have ownership rights, and that it can be exported in standard formats
Key Takeaways
Translation memory is not a luxury or an optional add-on. It is a fundamental technology that professional translation agencies use to deliver better, faster, and more cost-effective translations. Understanding how it works helps you:
- Make informed decisions about translation investments
- Evaluate translation providers effectively
- Maximize the long-term value of your multilingual content
- Ensure consistency across all your translated materials
Whether you are translating technical manuals, legal contracts, marketing materials, or website content, translation memory technology works in the background to protect your investment in quality translations. For more about choosing the right translation partner, see our guide to selecting a translation agency, or return to our complete translation services guide for a full overview of professional language solutions. Dutch speakers may also benefit from our vertaalbureau kennisbank for insights on working with translation agencies, or learn about beëdigde vertalingen when your projects require official sworn certification.
