1 Corinthians 2:14 says natural people cannot understand "the things" of the Spirit of God, but does not say whether this refers to some or all the things of the Spirit of God. But from the context, 1 Corinthians 3:1, we see that Paul spoke to un-spiritual people using Spiritual Milk, thus clearly teaching natural people can understand the spiritual milk things of the Spirit of God.
Scripture says God's word (the Law) acts as an escort of the lost (natural people) to Christ, again clearly teaching the lost can understand the milk of the gospel. Galatians 3:24.
In 2 Timothy 3:15 we learn that scripture provides the wisdom needed to lead the lost to salvation, again teaching the lost can understand spiritual milk, the fundamentals of the gospel.
Scripture says God's word (the Law) acts as an escort of the lost (natural people) to Christ, again clearly teaching the lost can understand the milk of the gospel. Galatians 3:24.
In 2 Timothy 3:15 we learn that scripture provides the wisdom needed to lead the lost to salvation, again teaching the lost can understand spiritual milk, the fundamentals of the gospel.