Declare Function ActivateKeyboardLayout Lib "user32" _
    (ByVal HKL As Long, _
    ByVal Flags As Long) As Long

Declare Function LoadKeyboardLayout Lib "user32" _
    Alias "LoadKeyboardLayoutA" _
    (ByVal pwszKLID As String, _
    ByVal Flags As Long) As Long

Const KbdRu = "00000419"
Const KbdEn = "00000409"

Sub SwitchToRu()
    Dim hLayout As Long
    hLayout = LoadKeyboardLayout(KbdRu, 0)
    ActivateKeyboardLayout hLayout, 0
End Sub

Sub SwitchToEn()
    Dim hLayout As Long
    hLayout = LoadKeyboardLayout(KbdEn, 0)
    ActivateKeyboardLayout hLayout, 0
End Sub