diff --git a/.claude-plugin/plugin.json b/.claude-plugin/plugin.json
index 1792306..bbbe8b7 100644
--- a/.claude-plugin/plugin.json
+++ b/.claude-plugin/plugin.json
@@ -26,7 +26,7 @@
     "voice": {
       "type": "string",
       "title": "Voice output",
-      "description": "Enable voice output (on / off / true / false, default: on)",
+      "description": "Enable voice output (on / off / true / false, default: off)",
       "sensitive": false
     },
     "style": {
diff --git a/README.en.md b/README.en.md
index 33209dc..1f3f0ce 100644
--- a/README.en.md
+++ b/README.en.md
@@ -4,7 +4,7 @@
 ![Shell](https://img.shields.io/badge/Shell-Bash-89e051?logo=gnu-bash&logoColor=white)
 ![GitHub Repo stars](https://img.shields.io/github/stars/chinadbo/cheerer?style=social)
 
-Whenever Claude Code finishes a task, cheerer plays a danmaku (bullet-screen) floating-subtitle animation and a multilingual voice encouragement to make coding more fun.
+Whenever Claude Code finishes a task, cheerer plays a danmaku (bullet-screen) floating-subtitle animation and a contextual encouragement message to make coding more fun. Voice output is available and can be enabled when you want spoken encouragement.
 
 ## ✨ Features
 
@@ -160,7 +160,7 @@ bash scripts/voices/cheer_ja.sh
 | `CHEERER_ENABLED` | Master switch | `true` / `false` | `true` |
 | `CHEERER_LANG` | Voice language | `zh` / `en` / `ja` / `ko` / `es` | `zh` |
 | `CHEERER_ANIM` | Animation style | `basketball` / `dance` / `fireworks` / `rocket` / `trophy` / `wave` / `epic` / `random` | `random` |
-| `CHEERER_VOICE` | Enable or disable voice | `on` / `off` / `true` / `false` | `on` |
+| `CHEERER_VOICE` | Enable or disable voice | `on` / `off` / `true` / `false` | `off` |
 | `CHEERER_DUMB` | Force text-only fallback or keep auto-detect | `auto` / `true` / `false` | `auto` |
 | `CHEERER_MODE` | Output mode | `auto` / `full` / `text` | `auto` |
 | `CHEERER_COOLDOWN` | Cooldown seconds between triggers | positive integer | `3` |
@@ -172,6 +172,8 @@ bash scripts/voices/cheer_ja.sh
 
 `CHEERER_*` env vars override plugin settings.
 
+Voice is opt-in on fresh installs. Leave CHEERER_VOICE unset (or set it to off) to keep cheerer text-first, and set it to on when you want spoken encouragement.
+
 ### Runtime behavior
 
 - `CHEERER_MODE=auto` animates `TaskCompleted` hooks and keeps `Stop` hooks text-only unless `CHEERER_INTENSITY=high`.
diff --git a/README.ja.md b/README.ja.md
index 0580b12..29eab94 100644
--- a/README.ja.md
+++ b/README.ja.md
@@ -6,7 +6,7 @@
 
 **言語：** [English](README.md) | [中文](README.zh.md) | 日本語
 
-Claude Code がタスクを完了すると、cheerer はターミナルで弾幕アニメーションと多言語の音声応援を再生し、コーディングをもっと楽しくします。
+Claude Code がタスクを完了すると、cheerer はターミナルで弾幕アニメーションと応援メッセージを表示し、コーディングをもっと楽しくします。音声応援が必要なときは音声出力を有効にできます。
 
 ## ✨ 主な機能
 
@@ -122,13 +122,15 @@ Claude Code が `/plugin enable cheerer` 中に設定入力を表示した場合
 /plugin enable cheerer
 > 音声言語（zh / en / ja / ko / es）: ja
 > アニメーション（random / basketball / dance / fireworks / rocket / trophy / wave / epic）: random
-> 音声出力（on / off）: on
+> 音声出力（on / off）: off
 > 応援スタイル（adaptive / balanced / hype / cozy）: adaptive
 > 応援の強さ（soft / normal / high）: normal
 ```
 
 入力プロンプトが表示されない場合は、同じ設定を環境変数で指定してください。
 
+新規インストールでは音声はオプトインです。CHEERER_VOICE を未設定のままにするか off に設定するとテキスト優先のままになり、音声応援が必要な場合だけ on にしてください。
+
 ### 方法2：環境変数
 
 `~/.bashrc` / `~/.zshrc` または `.claude/settings.json` に設定：
@@ -138,7 +140,7 @@ Claude Code が `/plugin enable cheerer` 中に設定入力を表示した場合
 | `CHEERER_ENABLED` | マスタースイッチ | `true` / `false` | `true` |
 | `CHEERER_LANG` | 音声言語 | `zh` / `en` / `ja` / `ko` / `es` | `zh` |
 | `CHEERER_ANIM` | アニメーション | `basketball` / `dance` / `fireworks` / `rocket` / `trophy` / `wave` / `epic` / `random` | `random` |
-| `CHEERER_VOICE` | 音声出力 | `on` / `off` / `true` / `false` | `on` |
+| `CHEERER_VOICE` | 音声出力 | `on` / `off` / `true` / `false` | `off` |
 | `CHEERER_DUMB` | テキストのみを強制するか自動判定を使う | `auto` / `true` / `false` | `auto` |
 | `CHEERER_MODE` | 出力モード | `auto` / `full` / `text` | `auto` |
 | `CHEERER_COOLDOWN` | トリガー間クールダウン（秒） | 正の整数 | `3` |
diff --git a/README.md b/README.md
index faf20fa..e049bdf 100644
--- a/README.md
+++ b/README.md
@@ -6,7 +6,7 @@
 
 **Language:** English | [中文](README.zh.md) | [日本語](README.ja.md)
 
-Whenever Claude Code finishes a task, cheerer plays a danmaku (bullet-screen) floating-subtitle animation and a multilingual voice encouragement to make coding more fun.
+Whenever Claude Code finishes a task, cheerer plays a danmaku (bullet-screen) floating-subtitle animation and a contextual encouragement message to make coding more fun. Voice output is available and can be enabled when you want spoken encouragement.
 
 ## ✨ Features
 
@@ -122,13 +122,15 @@ If Claude Code prompts for plugin settings during `/plugin enable cheerer`, you
 /plugin enable cheerer
 > Voice language (zh / en / ja): zh
 > Animation style (random / basketball / dance / fireworks / epic): random
-> Enable voice output (on / off): on
+> Enable voice output (on / off): off
 > Celebration style (adaptive / balanced / hype / cozy): adaptive
 > Celebration intensity (soft / normal / high): normal
 ```
 
 If no prompt appears, set the same values with environment variables instead.
 
+Voice is opt-in on fresh installs. Leave CHEERER_VOICE unset (or set it to off) to keep cheerer text-first, and set it to on when you want spoken encouragement.
+
 ### Option 2: Environment variables
 
 Set in your shell profile (`~/.bashrc`, `~/.zshrc`) or `.claude/settings.json`:
@@ -138,7 +140,7 @@ Set in your shell profile (`~/.bashrc`, `~/.zshrc`) or `.claude/settings.json`:
 | `CHEERER_ENABLED` | Master switch | `true` / `false` | `true` |
 | `CHEERER_LANG` | Voice language | `zh` / `en` / `ja` / `ko` / `es` | `zh` |
 | `CHEERER_ANIM` | Animation style | `basketball` / `dance` / `fireworks` / `rocket` / `trophy` / `wave` / `epic` / `random` | `random` |
-| `CHEERER_VOICE` | Voice output | `on` / `off` / `true` / `false` | `on` |
+| `CHEERER_VOICE` | Voice output | `on` / `off` / `true` / `false` | `off` |
 | `CHEERER_DUMB` | Force text-only fallback or keep auto-detect | `auto` / `true` / `false` | `auto` |
 | `CHEERER_MODE` | Output mode | `auto` / `full` / `text` | `auto` |
 | `CHEERER_COOLDOWN` | Cooldown between triggers (seconds) | positive integer | `3` |
diff --git a/README.zh.md b/README.zh.md
index de832b3..55a35db 100644
--- a/README.zh.md
+++ b/README.zh.md
@@ -6,7 +6,7 @@
 
 **语言：** [English](README.md) | 中文 | [日本語](README.ja.md)
 
-每当 Claude Code 完成任务时，在终端播放弹幕动画 + 多语言语音鼓励，让编码更快乐！
+每当 Claude Code 完成任务时，在终端播放弹幕动画与鼓励文字，让编码更快乐！开启语音后还可享受多语言语音鼓励。
 
 ## ✨ 功能
 
@@ -122,13 +122,15 @@ chmod +x ~/.cheerer/bin/cheer
 /plugin enable cheerer
 > 语音语言（zh / en / ja / ko / es）：zh
 > 动画类型（random / basketball / dance / fireworks / rocket / trophy / wave / epic）：random
-> 启用语音（on / off）：on
+> 启用语音（on / off）：off
 > 鼓励风格（adaptive / balanced / hype / cozy）：adaptive
 > 鼓励强度（soft / normal / high）：normal
 ```
 
 如果没有出现交互提示，也可以直接通过环境变量完成同样的配置。
 
+语音在全新安装时默认为可选关闭状态。保持 CHEERER_VOICE 未设置（或显式设为 off）即可维持纯文本优先，需要语音鼓励时再设为 on。
+
 ### 方式二：环境变量
 
 在 `~/.bashrc` / `~/.zshrc` 或 `.claude/settings.json` 中设置：
@@ -138,7 +140,7 @@ chmod +x ~/.cheerer/bin/cheer
 | `CHEERER_ENABLED` | 主开关 | `true` / `false` | `true` |
 | `CHEERER_LANG` | 语音语言 | `zh` / `en` / `ja` / `ko` / `es` | `zh` |
 | `CHEERER_ANIM` | 动画类型 | `basketball` / `dance` / `fireworks` / `rocket` / `trophy` / `wave` / `epic` / `random` | `random` |
-| `CHEERER_VOICE` | 语音开关 | `on` / `off` / `true` / `false` | `on` |
+| `CHEERER_VOICE` | 语音开关 | `on` / `off` / `true` / `false` | `off` |
 | `CHEERER_DUMB` | 强制纯文本降级或保持自动检测 | `auto` / `true` / `false` | `auto` |
 | `CHEERER_MODE` | 输出模式 | `auto` / `full` / `text` | `auto` |
 | `CHEERER_COOLDOWN` | 两次触发的冷却时间（秒） | 正整数 | `3` |
diff --git a/bin/cheer b/bin/cheer
index 59ec792..d6487bf 100755
--- a/bin/cheer
+++ b/bin/cheer
@@ -49,7 +49,7 @@ Environment variables:
   CHEERER_ENABLED        Master switch (true/false, default: true)
   CHEERER_LANG           Voice language (zh/en/ja/ko/es, default: zh)
   CHEERER_ANIM           Animation style (random/[name]/epic, default: random)
-  CHEERER_VOICE          Voice output (on/off, default: on)
+  CHEERER_VOICE          Voice output (on/off, default: off)
   CHEERER_STYLE          Celebration style (adaptive/balanced/hype/cozy)
   CHEERER_INTENSITY      Intensity (soft/normal/high)
   CHEERER_MODE           Output mode (auto/full/text)
diff --git a/scripts/lib/config.sh b/scripts/lib/config.sh
index 0de73c1..ec87650 100644
--- a/scripts/lib/config.sh
+++ b/scripts/lib/config.sh
@@ -70,7 +70,7 @@ config_apply_defaults() {
   CHEERER_ENABLED="${CHEERER_ENABLED:-true}"
   CHEERER_LANG="${CHEERER_LANG:-${CLAUDE_PLUGIN_OPTION_LANG:-zh}}"
   CHEERER_ANIM="${CHEERER_ANIM:-${CLAUDE_PLUGIN_OPTION_ANIM:-random}}"
-  CHEERER_VOICE="${CHEERER_VOICE:-${CLAUDE_PLUGIN_OPTION_VOICE:-on}}"
+  CHEERER_VOICE="${CHEERER_VOICE:-${CLAUDE_PLUGIN_OPTION_VOICE:-off}}"
   CHEERER_STYLE="${CHEERER_STYLE:-${CLAUDE_PLUGIN_OPTION_STYLE:-adaptive}}"
   CHEERER_INTENSITY="${CHEERER_INTENSITY:-${CLAUDE_PLUGIN_OPTION_INTENSITY:-normal}}"
   CHEERER_DUMB="${CHEERER_DUMB:-auto}"
diff --git a/scripts/lib/render.sh b/scripts/lib/render.sh
index aceeb38..5ad3463 100644
--- a/scripts/lib/render.sh
+++ b/scripts/lib/render.sh
@@ -155,7 +155,7 @@ render_emit() {
   fi
 
   export CHEERER_DUMB="${CHEERER_DUMB:-false}"
-  export CHEERER_VOICE="${CHEERER_VOICE:-on}"
+  export CHEERER_VOICE="${CHEERER_VOICE:-off}"
 
   if [[ -f "$voice_script" ]]; then
     bash "$voice_script"
diff --git a/scripts/voices/cheer.sh b/scripts/voices/cheer.sh
index f215351..def66de 100755
--- a/scripts/voices/cheer.sh
+++ b/scripts/voices/cheer.sh
@@ -24,7 +24,7 @@ else
   printf '\033[1;32m🎉 %s\033[0m\n' "$_msg"
 fi
 
-CHEERER_VOICE="${CHEERER_VOICE:-on}"
+CHEERER_VOICE="${CHEERER_VOICE:-off}"
 if [[ "$CHEERER_VOICE" == "off" ]] || [[ "$CHEERER_VOICE" == "false" ]]; then
   exit 0
 fi
diff --git a/tests/config_test.sh b/tests/config_test.sh
index fd0f768..73ef09a 100644
--- a/tests/config_test.sh
+++ b/tests/config_test.sh
@@ -5,6 +5,20 @@ ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
 . "$ROOT_DIR/tests/test_lib.sh"
 . "$ROOT_DIR/scripts/lib/config.sh"
 
+# ---------------------------------------------------------------------------
+# test_config_apply_defaults_uses_voice_off_when_unset
+# ---------------------------------------------------------------------------
+test_config_apply_defaults_uses_voice_off_when_unset() {
+  unset CHEERER_LANG CHEERER_ANIM CHEERER_VOICE CHEERER_STYLE CHEERER_INTENSITY \
+        CHEERER_DUMB CHEERER_MODE CHEERER_COOLDOWN CHEERER_ANIM_DURATION \
+        CHEERER_EPIC CHEERER_EPIC_THRESHOLD CHEERER_ENABLED 2>/dev/null || true
+  unset CLAUDE_PLUGIN_OPTION_VOICE 2>/dev/null || true
+
+  config_apply_defaults
+
+  assert_eq "off" "$CHEERER_VOICE" || return 1
+}
+
 # ---------------------------------------------------------------------------
 # test_config_apply_defaults_uses_plugin_options
 # ---------------------------------------------------------------------------
@@ -187,6 +201,7 @@ test_config_print_current_lists_effective_values() {
 # ---------------------------------------------------------------------------
 # Run
 # ---------------------------------------------------------------------------
+run_test "config_apply_defaults_uses_voice_off_when_unset"    test_config_apply_defaults_uses_voice_off_when_unset
 run_test "config_apply_defaults_uses_plugin_options"          test_config_apply_defaults_uses_plugin_options
 run_test "config_apply_defaults_normalizes_invalid_values"    test_config_apply_defaults_normalizes_invalid_values
 run_test "config_load_file_rejects_non_cheerer_lines"         test_config_load_file_rejects_non_cheerer_lines
diff --git a/tests/integration_test.sh b/tests/integration_test.sh
index 1f196ab..e4e3987 100644
--- a/tests/integration_test.sh
+++ b/tests/integration_test.sh
@@ -530,6 +530,7 @@ test_help_flag_shows_usage() {
   assert_contains "$output" "CHEERER_LANG"
   assert_contains "$output" "CHEERER_COOLDOWN"
   assert_contains "$output" "CHEERER_ANIM_DURATION"
+  assert_contains "$output" "CHEERER_VOICE          Voice output (on/off, default: off)"
 }
 
 test_config_flag_shows_values() {
@@ -545,6 +546,7 @@ test_config_flag_shows_defaults() {
   local output
   output="$(bash bin/cheer --config 2>&1)"
   assert_contains "$output" "CHEERER_LANG=zh"
+  assert_contains "$output" "CHEERER_VOICE=off"
   assert_contains "$output" "CHEERER_COOLDOWN=3"
   assert_contains "$output" "CHEERER_ANIM_DURATION=30"
 }
@@ -730,4 +732,49 @@ run_test "doctor_cli_reports_missing_optional_file_as_warn" test_doctor_cli_repo
 run_test "doctor_cli_exits_non_zero_for_invalid_animation" test_doctor_cli_exits_non_zero_for_invalid_animation
 run_test "why_cli_explains_short_task_fixture" test_why_cli_explains_short_task_fixture
 run_test "why_cli_uses_installed_plugin_root_resolution" test_why_cli_uses_installed_plugin_root_resolution
+
+test_shared_voice_script_defaults_off_when_unset() {
+  local tmp_dir bin_dir output
+  tmp_dir="$(make_tmp_dir)"
+  bin_dir="$tmp_dir/bin"
+  mkdir -p "$bin_dir"
+
+  printf '#!/bin/bash\nprintf "say-called\\n" >> "%s"\n' "$tmp_dir/voice.log" > "$bin_dir/say"
+  chmod +x "$bin_dir/say"
+
+  output="$(PATH="$bin_dir:$PATH" CHEERER_LANG="en" CHEERER_DUMB="true" bash scripts/voices/cheer.sh)"
+
+  assert_contains "$output" "🎉 Great work. Task complete."
+  [[ ! -f "$tmp_dir/voice.log" ]] || return 1
+}
+
+test_shared_voice_script_respects_explicit_on() {
+  local tmp_dir bin_dir i
+  tmp_dir="$(make_tmp_dir)"
+  bin_dir="$tmp_dir/bin"
+  mkdir -p "$bin_dir"
+
+  printf '#!/bin/bash\nsleep 0.6\nprintf "say-called\\n" > "%s"\n' "$tmp_dir/voice.log" > "$bin_dir/say"
+  chmod +x "$bin_dir/say"
+
+  PATH="$bin_dir:$PATH" CHEERER_LANG="en" CHEERER_DUMB="true" CHEERER_VOICE="on" bash scripts/voices/cheer.sh >/dev/null
+
+  for i in 1 2 3 4 5 6 7 8 9 10; do
+    [[ -f "$tmp_dir/voice.log" ]] && break
+    sleep 0.2
+  done
+
+  [[ -f "$tmp_dir/voice.log" ]] || return 1
+}
+
+run_test "shared_voice_script_defaults_off_when_unset" test_shared_voice_script_defaults_off_when_unset
+run_test "shared_voice_script_respects_explicit_on" test_shared_voice_script_respects_explicit_on
+
+test_plugin_manifest_reports_voice_default_off() {
+  local manifest
+  manifest="$(< .claude-plugin/plugin.json)"
+  assert_contains "$manifest" "Enable voice output (on / off / true / false, default: off)"
+}
+
+run_test "plugin_manifest_reports_voice_default_off" test_plugin_manifest_reports_voice_default_off
 finish_tests
diff --git a/tests/render_test.sh b/tests/render_test.sh
index fd68a94..db0a703 100644
--- a/tests/render_test.sh
+++ b/tests/render_test.sh
@@ -330,4 +330,32 @@ test_render_custom_message_skips_tab_only_lines() {
 }
 
 run_test "render_custom_message_skips_tab_only_lines" test_render_custom_message_skips_tab_only_lines
+
+test_render_emit_exports_voice_off_by_default() {
+  local tmp_dir result
+  tmp_dir="$(make_tmp_dir)"
+  mkdir -p "$tmp_dir/voices" "$tmp_dir/animations"
+
+  cat > "$tmp_dir/voices/cheer_en.sh" <<'VOICE_EOF'
+#!/bin/bash
+printf 'voice=%s\n' "${CHEERER_VOICE:-unset}"
+VOICE_EOF
+  chmod +x "$tmp_dir/voices/cheer_en.sh"
+
+  VOICE_DIR="$tmp_dir/voices"
+  ANIM_DIR="$tmp_dir/animations"
+  CHEERER_LANG="en"
+  unset CHEERER_VOICE 2>/dev/null || true
+  CHEERER_DUMB="true"
+  RENDER_ANIMATE="false"
+  IN_COOLDOWN="false"
+  RENDER_MESSAGE_TEXT="Text path still runs"
+  RENDER_MESSAGE_ID="voice_default_off"
+
+  result="$(render_emit)"
+
+  assert_contains "$result" "voice=off"
+}
+
+run_test "render_emit_exports_voice_off_by_default" test_render_emit_exports_voice_off_by_default
 finish_tests