diff --git a/src/test/fuzz/string.cpp b/src/test/fuzz/string.cpp
index 49bee0e81..3c1f911f7 100644
--- a/src/test/fuzz/string.cpp
+++ b/src/test/fuzz/string.cpp
@@ -119,4 +119,10 @@ void test_one_input(const std::vector<uint8_t>& buffer)
         int64_t amount_out;
         (void)ParseFixedPoint(random_string_1, fuzzed_data_provider.ConsumeIntegralInRange<int>(0, 1024), &amount_out);
     }
+    {
+        (void)Untranslated(random_string_1);
+        const bilingual_str bs1{random_string_1, random_string_2};
+        const bilingual_str bs2{random_string_2, random_string_1};
+        (void)(bs1 + bs2);
+    }
 }
diff --git a/src/test/fuzz/strprintf.cpp b/src/test/fuzz/strprintf.cpp
index d5be1070b..29064bc45 100644
--- a/src/test/fuzz/strprintf.cpp
+++ b/src/test/fuzz/strprintf.cpp
@@ -6,6 +6,7 @@
 #include <test/fuzz/fuzz.h>
 #include <tinyformat.h>
 #include <util/strencodings.h>
+#include <util/translation.h>
 
 #include <algorithm>
 #include <cstdint>
@@ -16,6 +17,7 @@ void test_one_input(const std::vector<uint8_t>& buffer)
 {
     FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size());
     const std::string format_string = fuzzed_data_provider.ConsumeRandomLengthString(64);
+    const bilingual_str bilingual_string{format_string, format_string};
 
     const int digits_in_format_specifier = std::count_if(format_string.begin(), format_string.end(), IsDigit);
 
@@ -47,50 +49,62 @@ void test_one_input(const std::vector<uint8_t>& buffer)
 
     try {
         (void)strprintf(format_string, (signed char*)nullptr);
+        (void)tinyformat::format(bilingual_string, (signed char*)nullptr);
     } catch (const tinyformat::format_error&) {
     }
     try {
         (void)strprintf(format_string, (unsigned char*)nullptr);
+        (void)tinyformat::format(bilingual_string, (unsigned char*)nullptr);
     } catch (const tinyformat::format_error&) {
     }
     try {
         (void)strprintf(format_string, (void*)nullptr);
+        (void)tinyformat::format(bilingual_string, (void*)nullptr);
     } catch (const tinyformat::format_error&) {
     }
     try {
         (void)strprintf(format_string, (bool*)nullptr);
+        (void)tinyformat::format(bilingual_string, (bool*)nullptr);
     } catch (const tinyformat::format_error&) {
     }
     try {
         (void)strprintf(format_string, (float*)nullptr);
+        (void)tinyformat::format(bilingual_string, (float*)nullptr);
     } catch (const tinyformat::format_error&) {
     }
     try {
         (void)strprintf(format_string, (double*)nullptr);
+        (void)tinyformat::format(bilingual_string, (double*)nullptr);
     } catch (const tinyformat::format_error&) {
     }
     try {
         (void)strprintf(format_string, (int16_t*)nullptr);
+        (void)tinyformat::format(bilingual_string, (int16_t*)nullptr);
     } catch (const tinyformat::format_error&) {
     }
     try {
         (void)strprintf(format_string, (uint16_t*)nullptr);
+        (void)tinyformat::format(bilingual_string, (uint16_t*)nullptr);
     } catch (const tinyformat::format_error&) {
     }
     try {
         (void)strprintf(format_string, (int32_t*)nullptr);
+        (void)tinyformat::format(bilingual_string, (int32_t*)nullptr);
     } catch (const tinyformat::format_error&) {
     }
     try {
         (void)strprintf(format_string, (uint32_t*)nullptr);
+        (void)tinyformat::format(bilingual_string, (uint32_t*)nullptr);
     } catch (const tinyformat::format_error&) {
     }
     try {
         (void)strprintf(format_string, (int64_t*)nullptr);
+        (void)tinyformat::format(bilingual_string, (int64_t*)nullptr);
     } catch (const tinyformat::format_error&) {
     }
     try {
         (void)strprintf(format_string, (uint64_t*)nullptr);
+        (void)tinyformat::format(bilingual_string, (uint64_t*)nullptr);
     } catch (const tinyformat::format_error&) {
     }
 
@@ -98,21 +112,27 @@ void test_one_input(const std::vector<uint8_t>& buffer)
         switch (fuzzed_data_provider.ConsumeIntegralInRange(0, 5)) {
         case 0:
             (void)strprintf(format_string, fuzzed_data_provider.ConsumeRandomLengthString(32));
+            (void)tinyformat::format(bilingual_string, fuzzed_data_provider.ConsumeRandomLengthString(32));
             break;
         case 1:
             (void)strprintf(format_string, fuzzed_data_provider.ConsumeRandomLengthString(32).c_str());
+            (void)tinyformat::format(bilingual_string, fuzzed_data_provider.ConsumeRandomLengthString(32).c_str());
             break;
         case 2:
             (void)strprintf(format_string, fuzzed_data_provider.ConsumeIntegral<signed char>());
+            (void)tinyformat::format(bilingual_string, fuzzed_data_provider.ConsumeIntegral<signed char>());
             break;
         case 3:
             (void)strprintf(format_string, fuzzed_data_provider.ConsumeIntegral<unsigned char>());
+            (void)tinyformat::format(bilingual_string, fuzzed_data_provider.ConsumeIntegral<unsigned char>());
             break;
         case 4:
             (void)strprintf(format_string, fuzzed_data_provider.ConsumeIntegral<char>());
+            (void)tinyformat::format(bilingual_string, fuzzed_data_provider.ConsumeIntegral<char>());
             break;
         case 5:
             (void)strprintf(format_string, fuzzed_data_provider.ConsumeBool());
+            (void)tinyformat::format(bilingual_string, fuzzed_data_provider.ConsumeBool());
             break;
         }
     } catch (const tinyformat::format_error&) {
@@ -138,27 +158,35 @@ void test_one_input(const std::vector<uint8_t>& buffer)
         switch (fuzzed_data_provider.ConsumeIntegralInRange(0, 7)) {
         case 0:
             (void)strprintf(format_string, fuzzed_data_provider.ConsumeFloatingPoint<float>());
+            (void)tinyformat::format(bilingual_string, fuzzed_data_provider.ConsumeFloatingPoint<float>());
             break;
         case 1:
             (void)strprintf(format_string, fuzzed_data_provider.ConsumeFloatingPoint<double>());
+            (void)tinyformat::format(bilingual_string, fuzzed_data_provider.ConsumeFloatingPoint<double>());
             break;
         case 2:
             (void)strprintf(format_string, fuzzed_data_provider.ConsumeIntegral<int16_t>());
+            (void)tinyformat::format(bilingual_string, fuzzed_data_provider.ConsumeIntegral<int16_t>());
             break;
         case 3:
             (void)strprintf(format_string, fuzzed_data_provider.ConsumeIntegral<uint16_t>());
+            (void)tinyformat::format(bilingual_string, fuzzed_data_provider.ConsumeIntegral<uint16_t>());
             break;
         case 4:
             (void)strprintf(format_string, fuzzed_data_provider.ConsumeIntegral<int32_t>());
+            (void)tinyformat::format(bilingual_string, fuzzed_data_provider.ConsumeIntegral<int32_t>());
             break;
         case 5:
             (void)strprintf(format_string, fuzzed_data_provider.ConsumeIntegral<uint32_t>());
+            (void)tinyformat::format(bilingual_string, fuzzed_data_provider.ConsumeIntegral<uint32_t>());
             break;
         case 6:
             (void)strprintf(format_string, fuzzed_data_provider.ConsumeIntegral<int64_t>());
+            (void)tinyformat::format(bilingual_string, fuzzed_data_provider.ConsumeIntegral<int64_t>());
             break;
         case 7:
             (void)strprintf(format_string, fuzzed_data_provider.ConsumeIntegral<uint64_t>());
+            (void)tinyformat::format(bilingual_string, fuzzed_data_provider.ConsumeIntegral<uint64_t>());
             break;
         }
     } catch (const tinyformat::format_error&) {