diff --git a/src/commonMain/kotlin/Executes.kt b/src/commonMain/kotlin/Executes.kt
index 751222d..795d1eb 100644
--- a/src/commonMain/kotlin/Executes.kt
+++ b/src/commonMain/kotlin/Executes.kt
@@ -7,7 +7,6 @@ import kotlinx.coroutines.delay
 import kotlinx.coroutines.isActive
 import kotlin.coroutines.coroutineContext
 
-
 /**
  * Execute [block] once at the [KronScheduler.next] time and return result of [block] calculation.
  *
@@ -55,7 +54,7 @@ suspend inline fun <T> KronScheduler.doOnceTz(noinline block: suspend (DateTimeT
  * @see buildSchedule
  */
 suspend inline fun <T> doOnce(
-    scheduleConfig: String,
+    @Language("CronExp") scheduleConfig: String,
     block: (DateTime) -> T
 ) = buildSchedule(scheduleConfig).doOnce(block)
 
@@ -64,7 +63,7 @@ suspend inline fun <T> doOnce(
  * @see buildSchedule
  */
 suspend inline fun <T> doOnceTz(
-    scheduleConfig: String,
+    @Language("CronExp") scheduleConfig: String,
     noinline block: suspend (DateTimeTz) -> T
 ) = buildSchedule(scheduleConfig).doOnceTz(block)
 
@@ -116,7 +115,7 @@ suspend inline fun KronScheduler.doWhileTz(noinline block: suspend (DateTimeTz)
  * @see buildSchedule
  */
 suspend inline fun doWhile(
-    scheduleConfig: String,
+    @Language("CronExp") scheduleConfig: String,
     block: (DateTime) -> Boolean
 ) = buildSchedule(scheduleConfig).doWhile(block)
 
@@ -127,7 +126,7 @@ suspend inline fun doWhile(
  */
 @Deprecated("Replaceable", ReplaceWith("doWhile", "dev.inmo.krontab.doWhile"))
 suspend inline fun doWhileLocal(
-    scheduleConfig: String,
+    @Language("CronExp") scheduleConfig: String,
     block: (DateTime) -> Boolean
 ) = doWhile(scheduleConfig, block)
 
@@ -137,7 +136,7 @@ suspend inline fun doWhileLocal(
  * @see buildSchedule
  */
 suspend inline fun doWhileTz(
-    scheduleConfig: String,
+    @Language("CronExp") scheduleConfig: String,
     noinline block: suspend (DateTimeTz) -> Boolean
 ) = buildSchedule(scheduleConfig).doWhileTz(block)
 
@@ -169,7 +168,7 @@ suspend inline fun KronScheduler.doInfinityTz(noinline block: suspend (DateTimeT
  * @see buildSchedule
  */
 suspend inline fun doInfinity(
-    scheduleConfig: String,
+    @Language("CronExp") scheduleConfig: String,
     block: (DateTime) -> Unit
 ) = buildSchedule(scheduleConfig).doInfinity(block)
 
@@ -180,7 +179,7 @@ suspend inline fun doInfinity(
  */
 @Deprecated("Replaceable", ReplaceWith("doInfinity", "dev.inmo.krontab.doInfinity"))
 suspend inline fun doInfinityLocal(
-    scheduleConfig: String,
+    @Language("CronExp") scheduleConfig: String,
     block: (DateTime) -> Unit
 ) = doInfinity(scheduleConfig, block)
 
@@ -190,6 +189,6 @@ suspend inline fun doInfinityLocal(
  * @see buildSchedule
  */
 suspend inline fun doInfinityTz(
-    scheduleConfig: String,
+    @Language("CronExp") scheduleConfig: String,
     noinline block: suspend (DateTimeTz) -> Unit
 ) = buildSchedule(scheduleConfig).doInfinityTz(block)
diff --git a/src/commonMain/kotlin/Language.kt b/src/commonMain/kotlin/Language.kt
new file mode 100644
index 0000000..70a57b4
--- /dev/null
+++ b/src/commonMain/kotlin/Language.kt
@@ -0,0 +1,6 @@
+package dev.inmo.krontab
+
+import kotlin.OptionalExpectation
+
+@OptionalExpectation
+internal expect annotation class Language(val value: String, val prefix: String = "", val suffix: String = "")
diff --git a/src/jvmMain/kotlin/Language.kt b/src/jvmMain/kotlin/Language.kt
new file mode 100644
index 0000000..7825f24
--- /dev/null
+++ b/src/jvmMain/kotlin/Language.kt
@@ -0,0 +1,5 @@
+package dev.inmo.krontab
+
+import org.intellij.lang.annotations.Language
+
+actual typealias Language = Language