In the example that I put create an array with the months, you can modify the words and show what you want:
<?php
$fechamovimiento = "2018-12-05T14:00";
$meses = ["Enero", "Febrero", "Marzo", "Abril", "Mayo", "Junio", "Julio", "Agosto", "Septiembre", "Octubre", "Noviembre", "Diciembre"];
$mes = substr($fechamovimiento, 5, -9);
if ($mes <= 12) {
echo $meses[$mes - 1];
}
else{
echo "Solo existen 12 meses hay un error en el formato de tu fecha: ".$fechamovimiento;
}
Basically what you do is create an array with the words, then as you already have the month separated from the date that is a number you go and you look for it within the array, subtracting one from it since if you had month 3 it would be March but in your array March is in position 2 because the array starts from 0, and if by error you get a month higher than 12 I put a message: