diff --git a/src/Smdn.Text.Ondulish/Smdn.Text.Ondulish/Translator.cs b/src/Smdn.Text.Ondulish/Smdn.Text.Ondulish/Translator.cs
index 90a5909..1e2a873 100644
--- a/src/Smdn.Text.Ondulish/Smdn.Text.Ondulish/Translator.cs
+++ b/src/Smdn.Text.Ondulish/Smdn.Text.Ondulish/Translator.cs
@@ -6,6 +6,7 @@
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
+using System.Reflection;
 using System.Text;
 
 using MeCab;
@@ -31,14 +32,12 @@ private void ThrowIfDisposed()
       throw new ObjectDisposedException(GetType().FullName);
   }
 
-  public static Tagger CreateTaggerForBundledDictionary(string processDirectoryPath)
+  public static Tagger CreateTaggerForBundledDictionary()
   {
-    if (processDirectoryPath is null)
-      throw new ArgumentNullException(nameof(processDirectoryPath));
-
-    var mecabDeploymentDirectoryPath = processDirectoryPath.Length == 0
+    var assemblyDirectory = System.IO.Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location);
+    var mecabDeploymentDirectoryPath = string.IsNullOrEmpty(assemblyDirectory)
       ? MeCabDeploymentDirectory // fallback: use relative path from current directory
-      : System.IO.Path.Join(processDirectoryPath, MeCabDeploymentDirectory);
+      : System.IO.Path.Join(assemblyDirectory, MeCabDeploymentDirectory);
 
     var pathToMeCabResourceFile = System.IO.Path.Join(mecabDeploymentDirectoryPath, "null.mecabrc");
     var pathToMeCabDictionaryDirectory = System.IO.Path.Join(mecabDeploymentDirectoryPath, "dic", "ipadic");
@@ -48,18 +47,9 @@ public static Tagger CreateTaggerForBundledDictionary(string processDirectoryPat
     return new Tagger(taggerArgs);
   }
 
-  private static string? GetProcessDirectory()
-#if SYSTEM_ENVIRONMENT_PROCESSPATH
-    => System.IO.Path.GetDirectoryName(Environment.ProcessPath);
-#else
-    => System.IO.Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().Location);
-#endif
-
   public Translator()
     : this(
-      tagger: CreateTaggerForBundledDictionary(
-        GetProcessDirectory() ?? string.Empty // fallback: use relative path from current directory
-      ),
+      tagger: CreateTaggerForBundledDictionary(),
       shouldDisposeTagger: true
     )
   {
diff --git a/tests/Smdn.Text.Ondulish/Smdn.Text.Ondulish/Translator.cs b/tests/Smdn.Text.Ondulish/Smdn.Text.Ondulish/Translator.cs
index ead95fb..81dc82c 100644
--- a/tests/Smdn.Text.Ondulish/Smdn.Text.Ondulish/Translator.cs
+++ b/tests/Smdn.Text.Ondulish/Smdn.Text.Ondulish/Translator.cs
@@ -10,16 +10,10 @@ namespace Smdn.Text.Ondulish;
 
 [TestFixture]
 public class TranslatorTests {
-  private static Translator Create()
-    => new(
-      tagger: Translator.CreateTaggerForBundledDictionary(processDirectoryPath: TestContext.CurrentContext.TestDirectory),
-      shouldDisposeTagger: true
-    );
-
   [Test]
   public void Ctor()
   {
-    using var t = Create();
+    using var t = new Translator();
 
     Assert.IsNotNull(t);
     Assert.DoesNotThrow(t.Dispose);
@@ -35,7 +29,7 @@ public void Ctor_ArgumentNull()
   [Test]
   public void Dispose()
   {
-    using var t = Create();
+    using var t = new Translator();
 
     Assert.DoesNotThrow(() => t.Translate("input", convertKatakanaToNarrow: true));
     Assert.DoesNotThrow(() => t.Translate("input", convertKatakanaToNarrow: false));
@@ -54,7 +48,7 @@ public void Dispose()
   [Test]
   public void Dispose_DisposeComposedTagger([Values(true, false)] bool shouldDisposeTagger)
   {
-    using var tagger = Translator.CreateTaggerForBundledDictionary(TestContext.CurrentContext.TestDirectory);
+    using var tagger = Translator.CreateTaggerForBundledDictionary();
     using var t = new Translator(
       tagger: tagger,
       shouldDisposeTagger: shouldDisposeTagger
@@ -89,7 +83,7 @@ public void Dispose_DisposeComposedTagger([Values(true, false)] bool shouldDispo
   [TestCase(@"オンドゥル😆😄", @"オンドゥル😆😄")]
   public void Translate(string input, string expected)
   {
-    using var t = Create();
+    using var t = new Translator();
 
     Assert.AreEqual(
       expected,
@@ -100,7 +94,7 @@ public void Translate(string input, string expected)
   [Test]
   public void Translate_SingleLine()
   {
-    using var t = Create();
+    using var t = new Translator();
 
     Assert.AreEqual(
       "オンドゥルルラギッタンディスカー",
@@ -119,7 +113,7 @@ public void Translate_MultipleLines()
 
 オンドゥルルラギッタンディスカー".Replace("\r", string.Empty).Replace("\n", Environment.NewLine);
 
-    using var t = Create();
+    using var t = new Translator();
 
     Assert.AreEqual(
       expected,
@@ -132,7 +126,7 @@ public void Translate_MultipleLines()
   [TestCase("めかぶ", "ﾍﾞｶﾑ")]
   public void Translate_ConvertKatakanaToNarrowDefaultValue(string input, string expected)
   {
-    using var t = Create();
+    using var t = new Translator();
 
     Assert.AreEqual(
       expected,
@@ -143,7 +137,7 @@ public void Translate_ConvertKatakanaToNarrowDefaultValue(string input, string e
   [Test]
   public void Translate_InputNull([Values(true, false)] bool convertKatakanaToNarrow)
   {
-    using var t = Create();
+    using var t = new Translator();
 
     Assert.Throws<ArgumentNullException>(() => t.Translate(input: null!, convertKatakanaToNarrow: convertKatakanaToNarrow));
   }
@@ -153,7 +147,7 @@ public void Translate_InputNull([Values(true, false)] bool convertKatakanaToNarr
   [TestCase("変身", "ヘシン")]
   public void Translate_ToTextWriter(string input, string expectedOutput)
   {
-    using var t = Create();
+    using var t = new Translator();
 
     var sb = new StringBuilder();
     var writer = new StringWriter(sb);
@@ -165,7 +159,7 @@ public void Translate_ToTextWriter(string input, string expectedOutput)
   [Test]
   public void Translate_ToTextWriter_InputNull([Values(true, false)] bool convertKatakanaToNarrow)
   {
-    using var t = Create();
+    using var t = new Translator();
 
     Assert.Throws<ArgumentNullException>(() => t.Translate(input: null!, convertKatakanaToNarrow: convertKatakanaToNarrow, output: TextWriter.Null));
   }
@@ -173,7 +167,7 @@ public void Translate_ToTextWriter_InputNull([Values(true, false)] bool convertK
   [Test]
   public void Translate_ToTextWriter_OutputNull([Values(true, false)] bool convertKatakanaToNarrow)
   {
-    using var t = Create();
+    using var t = new Translator();
 
     Assert.Throws<ArgumentNullException>(() => t.Translate(input: string.Empty, convertKatakanaToNarrow: convertKatakanaToNarrow, output: null!));
   }
@@ -186,7 +180,7 @@ public void Translate_ToTextWriter_OutputNull([Values(true, false)] bool convert
   [TestCase("あいするな", "ｱﾞｲﾄﾞｩﾙﾀﾞ")]
   public void Translate_ToNarrowKatakana(string input, string expected)
   {
-    using var t = Create();
+    using var t = new Translator();
 
     Assert.AreEqual(
       expected,
@@ -198,7 +192,7 @@ public void Translate_ToNarrowKatakana(string input, string expected)
   [TestCase("貴様、相手は俺だ", "クサム、アンギョン和田")]
   public void Translate_SpecialCase(string input, string expected)
   {
-    using var t = Create();
+    using var t = new Translator();
 
     Assert.AreEqual(
       expected,
@@ -222,7 +216,7 @@ public void Translate_SpecialCase(string input, string expected)
   [TestCase("おんどぅ", "オンドゥ")]
   public void Translate_Phoneme(string input, string expected)
   {
-    using var t = Create();
+    using var t = new Translator();
 
     Assert.AreEqual(
       expected,
@@ -233,7 +227,7 @@ public void Translate_Phoneme(string input, string expected)
   [Test]
   public void Translate_DictionaryTerm_Words()
   {
-    using var t = Create();
+    using var t = new Translator();
 
     foreach (var pair in t.WordDictionary) {
       const string inputPrepend = "あ";
@@ -251,7 +245,7 @@ public void Translate_DictionaryTerm_Words()
   [Test]
   public void Translate_DictionaryTerm_Phrases()
   {
-    using var t = Create();
+    using var t = new Translator();
 
     foreach (var pair in t.PhraseDictionary) {
       const string inputPrepend = "あ";