DOTextSample.cs

using System;
using DG.Tweening;
using UnityEngine;
using UnityEngine.UI;

// see also : http://dotween.demigiant.com/documentation.php
public class DOTextSample : MonoBehaviour
{
    public Text Text;

    void Start()
    {
        string[] textArray =
        {
            "<color=#008080>こ</color>",
            "<color=#778899>う</color>",
            "<color=#f5f5f5>で</color>",
            "<color=#008080>し</color>",
            "<color=#778899>ょ</color>",
            "<color=#f5f5f5>う</color>",
            "<color=#008080>か</color>",
            "<color=#778899>!</color>",
            "<color=#f5f5f5>?</color>"
        };

        this.Text.DOText(String.Join("", textArray), 1.0f)
            .SetEase(Ease.Linear)
            .Play();
    }
}