ArrayType and AbstractPersonalTranslation.

TranslatableEntity.orm.yml

Entity\TranslatableEntity:
    type: entity
    gedmo:
        translation:
            entity: Entity\Translation
    id:
        id:
            type: integer

    fields:
        some_array_data:
            type: array
            gedmo:
                - translatable

    oneToMany:
        translations:
            targetEntity: Entity\Translation
            mappedBy: object
            cascade: [ persist, remove ]

Translation.php

<?php

namespace Entity;

use Gedmo\Translatable\Entity\MappedSuperclass\AbstractPersonalTranslation;

class Translation extends AbstractPersonalTranslation
{
    public function setContent($value)
    {
        if (is_array($value)) {
            $value = serialize($value);
        }

        return parent::setContent($value);
    }
}