diff --git a/Marlin/src/HAL/HAL_LPC1768/main.cpp b/Marlin/src/HAL/HAL_LPC1768/main.cpp
index 5f4e672f385b8f73f51a8609872024905e437422..8941703f2ebc91694970b31b80c027a2fead3449 100644
--- a/Marlin/src/HAL/HAL_LPC1768/main.cpp
+++ b/Marlin/src/HAL/HAL_LPC1768/main.cpp
@@ -59,7 +59,7 @@ extern "C" {
 
   // Runs after clock init and before global static constructors
   void SystemPostInit() {
-    _millis = 0;                            // Initialise the millisecond counter value;
+    _millis = 0;                            // Initialize the millisecond counter value
     SysTick_Config(SystemCoreClock / 1000); // Start millisecond global counter
 
     // Runs before setup() need to configure LED_PIN and use to indicate succsessful bootloader execution
@@ -96,7 +96,7 @@ int main(void) {
   while (!USB_Configuration && PENDING(millis(), usb_timeout)) {
     delay(50);
     #if PIN_EXISTS(LED)
-      TOGGLE(LED_PIN);     // Flash fast while USB initialisation completes
+      TOGGLE(LED_PIN);     // Flash quickly during USB initialization
     #endif
   }
 
@@ -105,7 +105,7 @@ int main(void) {
     #if NUM_SERIAL > 1
       MYSERIAL1.begin(BAUDRATE);
     #endif
-    SERIAL_PRINTF("\n\necho:%s (%dMhz) Initialised\n", isLPC1769() ? "LPC1769" : "LPC1768", SystemCoreClock / 1000000);
+    SERIAL_PRINTF("\n\necho:%s (%dMhz) Initialized\n", isLPC1769() ? "LPC1769" : "LPC1768", SystemCoreClock / 1000000);
     SERIAL_FLUSHTX();
   #endif
 
diff --git a/Marlin/src/HAL/HAL_STM32F4/EEPROM_Emul/eeprom_emul.cpp b/Marlin/src/HAL/HAL_STM32F4/EEPROM_Emul/eeprom_emul.cpp
index 26ab2fc92c2247ee13112660d218fd518ff89231..7be880ace086549736e644be7a3b1c086e3c3ac9 100644
--- a/Marlin/src/HAL/HAL_STM32F4/EEPROM_Emul/eeprom_emul.cpp
+++ b/Marlin/src/HAL/HAL_STM32F4/EEPROM_Emul/eeprom_emul.cpp
@@ -78,7 +78,7 @@ static uint16_t EE_VerifyPageFullyErased(uint32_t Address);
   * @retval - Flash error code: on write Flash error
   *         - FLASH_COMPLETE: on success
   */
-uint16_t EE_Initialise(void) {
+uint16_t EE_Initialize(void) {
   uint16_t PageStatus0 = 6, PageStatus1 = 6;
   uint16_t VarIdx = 0;
   uint16_t EepromStatus = 0, ReadStatus = 0;
diff --git a/Marlin/src/HAL/HAL_STM32F4/EEPROM_Emul/eeprom_emul.h b/Marlin/src/HAL/HAL_STM32F4/EEPROM_Emul/eeprom_emul.h
index 476baee92fb7def089e4cda0e421091766974c7e..a7e3e0f012696af4426adce556ba1f6d73f6e883 100644
--- a/Marlin/src/HAL/HAL_STM32F4/EEPROM_Emul/eeprom_emul.h
+++ b/Marlin/src/HAL/HAL_STM32F4/EEPROM_Emul/eeprom_emul.h
@@ -108,7 +108,7 @@
 /* Exported types ------------------------------------------------------------*/
 /* Exported macro ------------------------------------------------------------*/
 /* Exported functions ------------------------------------------------------- */
-uint16_t EE_Initialise(void);
+uint16_t EE_Initialize(void);
 uint16_t EE_ReadVariable(uint16_t VirtAddress, uint16_t* Data);
 uint16_t EE_WriteVariable(uint16_t VirtAddress, uint16_t Data);
 
diff --git a/Marlin/src/HAL/HAL_STM32F4/EmulatedEeprom.cpp b/Marlin/src/HAL/HAL_STM32F4/EmulatedEeprom.cpp
index b76de3dbe81e3757df9157ed34a2f547a9c3a914..19853171fe615180ef8b3b55c7319e5367cb48ee 100644
--- a/Marlin/src/HAL/HAL_STM32F4/EmulatedEeprom.cpp
+++ b/Marlin/src/HAL/HAL_STM32F4/EmulatedEeprom.cpp
@@ -59,7 +59,7 @@
 // --------------------------------------------------------------------------
 // Private Variables
 // --------------------------------------------------------------------------
-static bool eeprom_initialised = false;
+static bool eeprom_initialized = false;
 // --------------------------------------------------------------------------
 // Function prototypes
 // --------------------------------------------------------------------------
@@ -82,17 +82,17 @@ static bool eeprom_initialised = false;
 
 
 void eeprom_init() {
-  if (!eeprom_initialised) {
+  if (!eeprom_initialized) {
     HAL_FLASH_Unlock();
 
     __HAL_FLASH_CLEAR_FLAG(FLASH_FLAG_EOP | FLASH_FLAG_OPERR | FLASH_FLAG_WRPERR |FLASH_FLAG_PGAERR | FLASH_FLAG_PGPERR | FLASH_FLAG_PGSERR);
 
     /* EEPROM Init */
-    if (EE_Initialise() != EE_OK)
+    if (EE_Initialize() != EE_OK)
       for (;;) HAL_Delay(1); // Spin forever until watchdog reset
 
     HAL_FLASH_Lock();
-    eeprom_initialised = true;
+    eeprom_initialized = true;
   }
 }
 
diff --git a/Marlin/src/HAL/HAL_STM32F4/HAL_timers_STM32F4.cpp b/Marlin/src/HAL/HAL_STM32F4/HAL_timers_STM32F4.cpp
index d03bf4c09b54b1439d73b94d696d31a52557ce31..64da993ef8efe28577460f4ff70a6e2c2e3c1b59 100644
--- a/Marlin/src/HAL/HAL_STM32F4/HAL_timers_STM32F4.cpp
+++ b/Marlin/src/HAL/HAL_STM32F4/HAL_timers_STM32F4.cpp
@@ -69,11 +69,11 @@ stm32f4_timer_t TimerHandle[NUM_HARDWARE_TIMERS];
 // Public functions
 // --------------------------------------------------------------------------
 
-bool timers_initialised[NUM_HARDWARE_TIMERS] = {false};
+bool timers_initialized[NUM_HARDWARE_TIMERS] = {false};
 
 void HAL_timer_start(const uint8_t timer_num, const uint32_t frequency) {
 
-  if (!timers_initialised[timer_num]) {
+  if (!timers_initialized[timer_num]) {
     constexpr uint32_t step_prescaler = STEPPER_TIMER_PRESCALE - 1,
                        temp_prescaler = TEMP_TIMER_PRESCALE - 1;
     switch (timer_num) {
@@ -111,7 +111,7 @@ void HAL_timer_start(const uint8_t timer_num, const uint32_t frequency) {
         HAL_NVIC_SetPriority(TEMP_TIMER_IRQ_ID, 2, 0);
         break;
     }
-    timers_initialised[timer_num] = true;
+    timers_initialized[timer_num] = true;
   }
 
   #ifdef STM32GENERIC
diff --git a/Marlin/src/HAL/HAL_STM32F7/EEPROM_Emul/eeprom_emul.cpp b/Marlin/src/HAL/HAL_STM32F7/EEPROM_Emul/eeprom_emul.cpp
index 029378561bec63b2ed2573426f36db3f3589e318..d28577758cab64f938ab3c5a12aafe6127b2db40 100644
--- a/Marlin/src/HAL/HAL_STM32F7/EEPROM_Emul/eeprom_emul.cpp
+++ b/Marlin/src/HAL/HAL_STM32F7/EEPROM_Emul/eeprom_emul.cpp
@@ -78,7 +78,7 @@ static uint16_t EE_VerifyPageFullyErased(uint32_t Address);
   * @retval - Flash error code: on write Flash error
   *         - FLASH_COMPLETE: on success
   */
-uint16_t EE_Initialise(void) {
+uint16_t EE_Initialize(void) {
   uint16_t PageStatus0 = 6, PageStatus1 = 6;
   uint16_t VarIdx = 0;
   uint16_t EepromStatus = 0, ReadStatus = 0;
diff --git a/Marlin/src/HAL/HAL_STM32F7/EEPROM_Emul/eeprom_emul.h b/Marlin/src/HAL/HAL_STM32F7/EEPROM_Emul/eeprom_emul.h
index d5c54985f568c5d1a870d5446dd48396e48c3177..8a45608ed981a30572b92ca2e00cf69921fbf85c 100644
--- a/Marlin/src/HAL/HAL_STM32F7/EEPROM_Emul/eeprom_emul.h
+++ b/Marlin/src/HAL/HAL_STM32F7/EEPROM_Emul/eeprom_emul.h
@@ -109,7 +109,7 @@
 /* Exported types ------------------------------------------------------------*/
 /* Exported macro ------------------------------------------------------------*/
 /* Exported functions ------------------------------------------------------- */
-uint16_t EE_Initialise(void);
+uint16_t EE_Initialize(void);
 uint16_t EE_ReadVariable(uint16_t VirtAddress, uint16_t* Data);
 uint16_t EE_WriteVariable(uint16_t VirtAddress, uint16_t Data);
 
diff --git a/Marlin/src/HAL/HAL_STM32F7/EmulatedEeprom.cpp b/Marlin/src/HAL/HAL_STM32F7/EmulatedEeprom.cpp
index 390ff35de5875fe73308e8a9144482d3c2e26659..0a7f5193f04af8d9989a69133582874e0f574ee0 100644
--- a/Marlin/src/HAL/HAL_STM32F7/EmulatedEeprom.cpp
+++ b/Marlin/src/HAL/HAL_STM32F7/EmulatedEeprom.cpp
@@ -57,7 +57,7 @@
 // --------------------------------------------------------------------------
 // Private Variables
 // --------------------------------------------------------------------------
-static bool eeprom_initialised = false;
+static bool eeprom_initialized = false;
 // --------------------------------------------------------------------------
 // Function prototypes
 // --------------------------------------------------------------------------
@@ -80,17 +80,17 @@ static bool eeprom_initialised = false;
 
 
 void eeprom_init() {
-  if (!eeprom_initialised) {
+  if (!eeprom_initialized) {
     HAL_FLASH_Unlock();
 
     __HAL_FLASH_CLEAR_FLAG(FLASH_FLAG_EOP | FLASH_FLAG_OPERR | FLASH_FLAG_WRPERR |FLASH_FLAG_PGAERR | FLASH_FLAG_PGPERR | FLASH_FLAG_PGSERR);
 
     /* EEPROM Init */
-    if (EE_Initialise() != EE_OK)
+    if (EE_Initialize() != EE_OK)
       for (;;) HAL_Delay(1); // Spin forever until watchdog reset
 
     HAL_FLASH_Lock();
-    eeprom_initialised = true;
+    eeprom_initialized = true;
   }
 }
 
diff --git a/Marlin/src/HAL/HAL_STM32F7/HAL_timers_STM32F7.cpp b/Marlin/src/HAL/HAL_STM32F7/HAL_timers_STM32F7.cpp
index 9454b71c812f0e1789ced16875c77a4bbb4ab875..c6b22fd441cfc0621decfd4f28e90cc15a9a026a 100644
--- a/Marlin/src/HAL/HAL_STM32F7/HAL_timers_STM32F7.cpp
+++ b/Marlin/src/HAL/HAL_STM32F7/HAL_timers_STM32F7.cpp
@@ -69,11 +69,11 @@ tTimerConfig timerConfig[NUM_HARDWARE_TIMERS];
 // --------------------------------------------------------------------------
 
 
-bool timers_initialised[NUM_HARDWARE_TIMERS] = {false};
+bool timers_initialized[NUM_HARDWARE_TIMERS] = {false};
 
 void HAL_timer_start(const uint8_t timer_num, const uint32_t frequency) {
 
-  if (!timers_initialised[timer_num]) {
+  if (!timers_initialized[timer_num]) {
     switch (timer_num) {
       case STEP_TIMER_NUM:
       //STEPPER TIMER TIM5 //use a 32bit timer
@@ -100,7 +100,7 @@ void HAL_timer_start(const uint8_t timer_num, const uint32_t frequency) {
       HAL_NVIC_SetPriority(timerConfig[1].IRQ_Id, 2, 0);
       break;
     }
-    timers_initialised[timer_num] = true;
+    timers_initialized[timer_num] = true;
   }
 
   timerConfig[timer_num].timerdef.Init.Period = (((HAL_TIMER_RATE) / timerConfig[timer_num].timerdef.Init.Prescaler) / frequency) - 1;
diff --git a/Marlin/src/HAL/HAL_TEENSY35_36/HAL_spi_Teensy.cpp b/Marlin/src/HAL/HAL_TEENSY35_36/HAL_spi_Teensy.cpp
index 3be0fdd3afd2cb0850aa7e3531de7d868ee19e81..6220225a1d1a838cc858cfbf43ac710a288f6cd1 100644
--- a/Marlin/src/HAL/HAL_TEENSY35_36/HAL_spi_Teensy.cpp
+++ b/Marlin/src/HAL/HAL_TEENSY35_36/HAL_spi_Teensy.cpp
@@ -9,7 +9,7 @@
 static SPISettings spiConfig;
 
 // Standard SPI functions
-/** Initialise SPI bus */
+/** Initialize SPI bus */
 void spiBegin(void) {
   #if !PIN_EXISTS(SS)
     #error SS_PIN not defined!
diff --git a/Marlin/src/HAL/shared/HAL_SPI.h b/Marlin/src/HAL/shared/HAL_SPI.h
index c011436b77b5223e8ea31e3d7e937c99d8a9a6a5..388b9f9cfb7dc4f051e5ae38114f4e5ec6189005 100644
--- a/Marlin/src/HAL/shared/HAL_SPI.h
+++ b/Marlin/src/HAL/shared/HAL_SPI.h
@@ -64,7 +64,7 @@
 #define SPI_DATAMODE_3 0x0C
 
 // Standard SPI functions
-/** Initialise SPI bus */
+/** Initialize SPI bus */
 void spiBegin(void);
 /** Configure SPI for specified SPI speed */
 void spiInit(uint8_t spiRate);
diff --git a/Marlin/src/HAL/shared/I2cEeprom.cpp b/Marlin/src/HAL/shared/I2cEeprom.cpp
index 792f2c65f691d271c21745da480ea0deeb0dbc29..a73cefa2d313abac18b29d4bea9ceaa6d2458a77 100644
--- a/Marlin/src/HAL/shared/I2cEeprom.cpp
+++ b/Marlin/src/HAL/shared/I2cEeprom.cpp
@@ -75,10 +75,10 @@
 static uint8_t eeprom_device_address = 0x50;
 
 static void eeprom_init(void) {
-  static bool eeprom_initialised = false;
-  if (!eeprom_initialised) {
+  static bool eeprom_initialized = false;
+  if (!eeprom_initialized) {
     Wire.begin();
-    eeprom_initialised = true;
+    eeprom_initialized = true;
   }
 }
 
diff --git a/Marlin/src/HAL/shared/backtrace/unwarm.cpp b/Marlin/src/HAL/shared/backtrace/unwarm.cpp
index f6d85b708b54c33a2a2e75eda6ffeed64a7fd4c9..13079817bacbe67bdcd1020ea6f82bff5297642f 100644
--- a/Marlin/src/HAL/shared/backtrace/unwarm.cpp
+++ b/Marlin/src/HAL/shared/backtrace/unwarm.cpp
@@ -51,7 +51,7 @@ void UnwInvalidateRegisterFile(RegData *regFile) {
 
 
 /**
- * Initialise the data used for unwinding.
+ * Initialize the data used for unwinding.
  */
 void UnwInitState(UnwState * const state,     /**< Pointer to structure to fill. */
                   const UnwindCallbacks *cb,  /**< Callbacks. */
diff --git a/Marlin/src/HAL/shared/backtrace/unwinder.cpp b/Marlin/src/HAL/shared/backtrace/unwinder.cpp
index 66281670c6dc9782d1aa1641874b3a5885b3704c..9c3001616574d821056f9756012a433d4d671408 100644
--- a/Marlin/src/HAL/shared/backtrace/unwinder.cpp
+++ b/Marlin/src/HAL/shared/backtrace/unwinder.cpp
@@ -44,7 +44,7 @@ UnwResult UnwindStart(UnwindFrame* frame, const UnwindCallbacks *cb, void *data)
     /* We don't have unwind information tables */
     UnwState state;
 
-    /* Initialise the unwinding state */
+    /* Initialize the unwinding state */
     UnwInitState(&state, cb, data, frame->pc, frame->sp);
 
     /* Check the Thumb bit */
diff --git a/Marlin/src/feature/I2CPositionEncoder.cpp b/Marlin/src/feature/I2CPositionEncoder.cpp
index d817f1400c6a774f695bcb12a73fffbaea717647..f5bec8885c807f7f0e382ff3c624e8d1523e1157 100644
--- a/Marlin/src/feature/I2CPositionEncoder.cpp
+++ b/Marlin/src/feature/I2CPositionEncoder.cpp
@@ -45,7 +45,7 @@ void I2CPositionEncoder::init(const uint8_t address, const AxisEnum axis) {
   encoderAxis = axis;
   i2cAddress = address;
 
-  initialised++;
+  initialized++;
 
   SERIAL_ECHOPAIR("Setting up encoder on ", axis_codes[encoderAxis]);
   SERIAL_ECHOLNPAIR(" axis, addr = ", address);
@@ -54,7 +54,7 @@ void I2CPositionEncoder::init(const uint8_t address, const AxisEnum axis) {
 }
 
 void I2CPositionEncoder::update() {
-  if (!initialised || !homed || !active) return; //check encoder is set up and active
+  if (!initialized || !homed || !active) return; //check encoder is set up and active
 
   position = get_position();
 
@@ -98,7 +98,7 @@ void I2CPositionEncoder::update() {
         SERIAL_ECHOLNPGM(" axis has been fault-free for set duration, reinstating error correction.");
 
         //the encoder likely lost its place when the error occured, so we'll reset and use the printer's
-        //idea of where it the axis is to re-initialise
+        //idea of where it the axis is to re-initialize
         const float pos = planner.get_axis_position_mm(encoderAxis);
         int32_t positionInTicks = pos * get_ticks_unit();
 
@@ -712,7 +712,7 @@ void I2CPositionEncodersMgr::change_module_address(const uint8_t oldaddr, const
   SERIAL_ECHOLNPGM("Address change successful!");
 
   // Now, if this module is configured, find which encoder instance it's supposed to correspond to
-  // and enable it (it will likely have failed initialisation on power-up, before the address change).
+  // and enable it (it will likely have failed initialization on power-up, before the address change).
   const int8_t idx = idx_from_addr(newaddr);
   if (idx >= 0 && !encoders[idx].get_active()) {
     SERIAL_ECHO(axis_codes[encoders[idx].get_axis()]);
diff --git a/Marlin/src/feature/I2CPositionEncoder.h b/Marlin/src/feature/I2CPositionEncoder.h
index 224e0da8b22de003e2c247608213c25866f253ec..f5fe8bced8c6ef25e038f98832d0f515659057ae 100644
--- a/Marlin/src/feature/I2CPositionEncoder.h
+++ b/Marlin/src/feature/I2CPositionEncoder.h
@@ -120,7 +120,7 @@ class I2CPositionEncoder {
 
     bool      homed               = false,
               trusted             = false,
-              initialised         = false,
+              initialized         = false,
               active              = false,
               invert              = false,
               ec                  = true;
diff --git a/frameworks/CMSIS/LPC1768/include/core_cm3.h b/frameworks/CMSIS/LPC1768/include/core_cm3.h
index 76bf26f6e39604169481e33866feb39e8e64af62..b09ff8db474ee9f4e1c7032902461b9c0c590fba 100644
--- a/frameworks/CMSIS/LPC1768/include/core_cm3.h
+++ b/frameworks/CMSIS/LPC1768/include/core_cm3.h
@@ -1120,7 +1120,7 @@ static __INLINE void NVIC_SystemReset(void)
 
 /** \brief  System Tick Configuration
 
-    This function initialises the system tick timer and its interrupt and start the system tick timer.
+    This function initializes the system tick timer and its interrupt and start the system tick timer.
     Counter is in free running mode to generate periodical interrupts.
 
     \param [in]  ticks  Number of ticks between two interrupts
diff --git a/frameworks/CMSIS/LPC1768/lib/usb/cdcuser.cpp b/frameworks/CMSIS/LPC1768/lib/usb/cdcuser.cpp
index 4f6f0a337a4a22762b08c1d0d1e74baab895c36d..23805ba93a3689d2044fb4c0eb9c819df265d94b 100644
--- a/frameworks/CMSIS/LPC1768/lib/usb/cdcuser.cpp
+++ b/frameworks/CMSIS/LPC1768/lib/usb/cdcuser.cpp
@@ -71,7 +71,7 @@ uint32_t CDC_OutBufAvailChar(uint32_t *availChar) {
 /* end Buffer handling */
 
 /*----------------------------------------------------------------------------
- CDC Initialisation
+ CDC Initialization
  Initializes the data structures and serial port
  Parameters:   None
  Return Value: None